diff --git a/jubeatools/formats/__init__.py b/jubeatools/formats/__init__.py
index efc586d..32a11c0 100644
--- a/jubeatools/formats/__init__.py
+++ b/jubeatools/formats/__init__.py
@@ -8,7 +8,7 @@ from path import Path
 
 from jubeatools.song import Song
 
-from .memo.mono_column import dump_mono_column, load_mono_column
+from .jubeat_analyser.mono_column import dump_mono_column, load_mono_column
 from .memon import (
     dump_memon_0_1_0,
     dump_memon_0_2_0,
diff --git a/jubeatools/formats/jubeat_analyser/__init__.py b/jubeatools/formats/jubeat_analyser/__init__.py
new file mode 100644
index 0000000..b0241c0
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/__init__.py
@@ -0,0 +1,17 @@
+"""
+Formats read by jubeat analyser
+
+memo is a vague term refering to several legacy formats.
+They were originally derived from the (somewhat) human-readable format choosen
+by websites storing official jubeat charts in text form as a memory aid.
+
+The machine-readable variants are partially documented (in japanese)
+on these pages :
+- http://yosh52.web.fc2.com/jubeat/fumenformat.html
+- http://yosh52.web.fc2.com/jubeat/holdmarker.html
+"""
+
+from .mono_column.dump import dump_mono_column
+from .mono_column.load import load_mono_column
+from .memo.dump import dump_memo
+from .memo.load import load_memo
diff --git a/jubeatools/formats/memo/command.py b/jubeatools/formats/jubeat_analyser/command.py
similarity index 67%
rename from jubeatools/formats/memo/command.py
rename to jubeatools/formats/jubeat_analyser/command.py
index b4958f6..03b2924 100644
--- a/jubeatools/formats/memo/command.py
+++ b/jubeatools/formats/jubeat_analyser/command.py
@@ -1,6 +1,29 @@
 """
-Useful things to parse and dump the header of analyser-like formats
+Useful things to parse and dump the jubeat analyser command format
+
+Known simple commands :
+  - b=<decimal>   : beats per measure (4 by default)
+  - m="<path>"    : music file path
+  - o=<int>       : offset in ms (100 by default)
+  - r=<int>       : ? increase the offset ? (in ms) (not supported, couldn't find any examples, wtf is it for ?)
+  - t=<decimal>   : tempo
+  
+Known hash commands :
+  - #memo             # youbeat-like format but a bar division always means a 1/4 note (amongst other quirks)
+  - #memo1            # youbeat-like but without bpm changes in the bar
+  - #memo2            # youbeat-like with memo symbols
+  - #boogie           # youbeat-like
+  - #pw=<int>         # number of panels horizontally (4 by default)
+  - #ph=<int>         # number of panels vertically (4 by default)
+  - #lev=<int>        # chart level (typically 1 to 10)
+  - #dif={1, 2, 3}    # 1: BSC, 2: ADV, 3: EXT
+  - #title="<str>"    # music title
+  - #artist="<str>"   # artist's name
+  - #jacket="<path>"  # music cover art path
+  - #prevpos=<int>    # preview start (in ms)
+  - #bpp              # bytes per panel (2 by default)
 """
+
 from decimal import Decimal
 from numbers import Number
 from typing import Any, Iterable, List, Optional, Tuple, Union
diff --git a/jubeatools/formats/jubeat_analyser/files.py b/jubeatools/formats/jubeat_analyser/files.py
new file mode 100644
index 0000000..f827edc
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/files.py
@@ -0,0 +1,20 @@
+from path import Path
+from typing import Dict, List
+
+def load_files(path: Path) -> Dict[Path, List[str]]:
+    # The vast majority of memo files you will encounter will be propely
+    # decoded using shift_jis_2004. Get ready for endless fun with the small
+    # portion of files that won't
+    files = {}
+    if path.isdir():
+        for f in path.files("*.txt"):
+            _load_file(f, files)
+    elif path.isfile():
+        _load_file(path, files)
+    return files
+
+def _load_file(path: Path, files: Dict[Path, List[str]]):
+    try:
+        files[path] = path.lines('shift_jis_2004')
+    except UnicodeDecodeError:
+        pass
\ No newline at end of file
diff --git a/jubeatools/formats/jubeat_analyser/memo/__init__.py b/jubeatools/formats/jubeat_analyser/memo/__init__.py
new file mode 100644
index 0000000..de673e7
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/memo/__init__.py
@@ -0,0 +1,11 @@
+"""
+memo
+
+#memo is the first (and probably oldest) youbeat-like format jubeat analyser
+supports, the japanese docs give a good overview of what it looks like :
+
+http://yosh52.web.fc2.com/jubeat/fumenformat.html
+"""
+
+from .dump import dump_memo
+from .load import load_memo
diff --git a/jubeatools/formats/jubeat_analyser/memo/dump.py b/jubeatools/formats/jubeat_analyser/memo/dump.py
new file mode 100644
index 0000000..2145a10
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/memo/dump.py
@@ -0,0 +1,2 @@
+def dump_memo(song):
+    ...
\ No newline at end of file
diff --git a/jubeatools/formats/jubeat_analyser/memo/load.py b/jubeatools/formats/jubeat_analyser/memo/load.py
new file mode 100644
index 0000000..77d4d59
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/memo/load.py
@@ -0,0 +1,43 @@
+from jubeatools.song import Song
+from path import Path
+from ..parser import JubeatAnalyserParser
+from dataclasses import dataclass
+from typing import List
+
+
+
+class MemoParser(JubeatAnalyserParser):
+    def __init__(self):
+        super().__init__()
+        self.sections: List[MemoLoadedSection] = []
+    
+    def do_memo(self):
+        ...
+        
+    def do_memo1(self):
+        raise ValueError("This is not a memo file")
+
+    do_boogie = do_memo2 = do_memo1
+
+    def do_bpp(self, value):
+        if self.sections:
+            raise ValueError(
+                "jubeatools does not handle changing the bytes per panel value halfway"
+            )
+        else:
+            super().do_bpp(value)
+    
+
+    def append_chart_line(self, position: str):
+        if self.bytes_per_panel == 1 and len(line) != 4:
+            raise SyntaxError(f"Invalid chart line for #bpp=1 : {line}")
+        elif self.bytes_per_panel == 2 and len(line.encode("shift_jis_2004")) != 8:
+            raise SyntaxError(f"Invalid chart line for #bpp=2 : {line}")
+        self.current_chart_lines.append(line)
+
+def load_memo(path: Path) -> Song:
+    # The vast majority of memo files you will encounter will be propely
+    # decoded using shift_jis_2004. Get ready for endless fun with the small
+    # portion of files that won't
+    with open(path, encoding="shift_jis_2004") as f:
+        lines = f.readlines()
\ No newline at end of file
diff --git a/jubeatools/formats/jubeat_analyser/mono_column/__init__.py b/jubeatools/formats/jubeat_analyser/mono_column/__init__.py
new file mode 100644
index 0000000..673fcf1
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/mono_column/__init__.py
@@ -0,0 +1,26 @@
+"""
+Mono column (not an official name)
+
+It's the format jubeat analyser expects when otherwise no format command has
+been found (like #memo #memo1 #memo2 or #boogie)
+
+Mono-column files are usually properly decoded using `shift_jis_2004`
+
+Mono-column files are made up of several sections.
+Each section is made up of a series of command lines and chart lines.
+The section end is marked by a line starting with "--"
+
+Command lines follow the usual jubeat analyser command pattern
+
+Chart lines come in groups of 4 in each section.
+A group of 4 chart lines makes up a frame, which contains the note symbols.
+
+Note symbols encode both the position and the time. The position is determined
+"visually" by the position the note symbol occupies in the frame.
+The time within the frame is determined by the precise symbol used.
+
+The default note symbols are the circled numbers from ① to ⑯, they represent
+"""
+
+from .dump import dump_mono_column
+from .load import load_mono_column
diff --git a/jubeatools/formats/memo/mono_column/dump.py b/jubeatools/formats/jubeat_analyser/mono_column/dump.py
similarity index 99%
rename from jubeatools/formats/memo/mono_column/dump.py
rename to jubeatools/formats/jubeat_analyser/mono_column/dump.py
index 8d7c585..51eecbf 100644
--- a/jubeatools/formats/memo/mono_column/dump.py
+++ b/jubeatools/formats/jubeat_analyser/mono_column/dump.py
@@ -23,7 +23,7 @@ from jubeatools.song import (
 )
 
 from ..command import dump_command
-from .commons import CIRCLE_FREE_SYMBOLS, NOTE_SYMBOLS
+from ..symbols import CIRCLE_FREE_SYMBOLS, NOTE_SYMBOLS
 
 COMMAND_ORDER = [
     "b",
diff --git a/jubeatools/formats/memo/mono_column/load.py b/jubeatools/formats/jubeat_analyser/mono_column/load.py
similarity index 78%
rename from jubeatools/formats/memo/mono_column/load.py
rename to jubeatools/formats/jubeat_analyser/mono_column/load.py
index 0620043..2ed270b 100644
--- a/jubeatools/formats/memo/mono_column/load.py
+++ b/jubeatools/formats/jubeat_analyser/mono_column/load.py
@@ -7,6 +7,7 @@ from decimal import Decimal
 from enum import Enum
 from itertools import product
 from typing import Dict, Iterator, List, Set, Tuple
+from functools import reduce
 
 import constraint
 from parsimonious import Grammar, NodeVisitor, ParseError
@@ -27,8 +28,10 @@ from jubeatools.song import (
 )
 
 from ..command import is_command, parse_command
-from ..symbol import is_symbol_definition, parse_symbol_definition
-from .commons import CIRCLE_FREE_SYMBOLS, NOTE_SYMBOLS
+from ..files import load_files
+from ..parser import JubeatAnalyserParser
+from ..symbol_definition import is_symbol_definition, parse_symbol_definition
+from ..symbols import CIRCLE_FREE_SYMBOLS, NOTE_SYMBOLS
 
 mono_column_chart_line_grammar = Grammar(
     r"""
@@ -211,127 +214,23 @@ def decimal_to_beats(current_beat: Decimal, symbol_timing: Decimal) -> BeatsTime
     return BeatsTime(decimal_time).limit_denominator(240)
 
 
-class MonoColumnParser:
+class MonoColumnParser(JubeatAnalyserParser):
     def __init__(self):
-        self.music = None
-        self.symbols = deepcopy(SYMBOL_TO_DECIMAL_TIME)
-        self.current_beat = Decimal("0")
-        self.current_tempo = None
-        self.current_chart_lines = []
-        self.timing_events = []
-        self.offset = 0
-        self.beats_per_section = 4
-        self.bytes_per_panel = 2
-        self.level = 1
-        self.difficulty = None
-        self.title = None
-        self.artist = None
-        self.jacket = None
-        self.preview_start = None
-        self.hold_by_arrow = False
-        self.circle_free = False
+        super().__init__()
         self.sections: List[MonoColumnLoadedSection] = []
 
-    def handle_command(self, command, value=None):
-        try:
-            method = getattr(self, f"do_{command}")
-        except AttributeError:
-            raise SyntaxError(f"Unknown analyser command : {command}") from None
-
-        if value is not None:
-            method(value)
-        else:
-            method()
-
-    def do_m(self, value):
-        self.music = value
-
-    def do_t(self, value):
-        self.current_tempo = Decimal(value)
-        self.timing_events.append(BPMEvent(self.current_beat, BPM=self.current_tempo))
-
-    def do_o(self, value):
-        self.offset = int(value)
-
-    def do_b(self, value):
-        self.beats_per_section = Decimal(value)
-
     def do_memo(self):
         raise ValueError("This is not a mono-column file")
 
     do_boogie = do_memo2 = do_memo1 = do_memo
 
-    def do_pw(self, value):
-        if int(value) != 4:
-            raise ValueError("jubeatools only supports 4×4 charts")
-
-    do_ph = do_pw
-
-    def do_lev(self, value):
-        self.level = int(value)
-
-    def do_dif(self, value):
-        dif = int(value)
-        if dif <= 0:
-            raise ValueError(f"Unknown chart difficulty : {dif}")
-        if dif < 4:
-            self.difficulty = DIFFICULTIES[dif]
-        else:
-            self.difficulty = f"EDIT-{dif-3}"
-
-    def do_title(self, value):
-        self.title = value
-
-    def do_artist(self, value):
-        self.artist = value
-
-    def do_jacket(self, value):
-        self.jacket = value
-
-    def do_prevpos(self, value):
-        self.preview_start = int(value)
-
     def do_bpp(self, value):
-        bpp = int(value)
         if self.sections:
             raise ValueError(
                 "jubeatools does not handle changing the bytes per panel value halfway"
             )
-        elif bpp not in (1, 2):
-            raise ValueError(f"Unexcpected bpp value : {value}")
-        elif self.circle_free and bpp == 1:
-            raise ValueError("#bpp can only be 2 when #circlefree is activated")
         else:
-            self.bytes_per_panel = int(value)
-
-    def do_holdbyarrow(self, value):
-        self.hold_by_arrow = int(value) == 1
-
-    def do_holdbytilde(self, value):
-        if int(value):
-            raise ValueError("jubeatools does not support #holdbytilde")
-
-    def do_circlefree(self, raw_value):
-        activate = bool(int(raw_value))
-        if activate and self.bytes_per_panel != 2:
-            raise ValueError("#circlefree can only be activated when #bpp=2")
-        self.circle_free = activate
-
-    def define_symbol(self, symbol: str, timing: Decimal):
-        bpp = self.bytes_per_panel
-        length_as_shift_jis = len(symbol.encode("shift_jis_2004"))
-        if length_as_shift_jis != bpp:
-            raise ValueError(
-                f"Invalid symbol definition. Since #bpp={bpp}, timing symbols "
-                f"should be {bpp} bytes long but '{symbol}' is {length_as_shift_jis}"
-            )
-        if timing > self.beats_per_section:
-            message = (
-                "Invalid symbol definition conscidering the number of beats per section :\n"
-                f"*{symbol}:{timing}"
-            )
-            raise ValueError(message)
-        self.symbols[symbol] = timing
+            super().do_bpp(value)
 
     def move_to_next_section(self):
         if len(self.current_chart_lines) % 4 != 0:
@@ -369,7 +268,7 @@ class MonoColumnParser:
         elif is_separator(line):
             self.move_to_next_section()
         elif not is_empty_line(line):
-            raise SyntaxError(f"not a valid #memo line : {line}")
+            raise SyntaxError(f"not a valid mono-column file line : {line}")
 
     def notes(self) -> Iterator[Union[TapNote, LongNote]]:
         if self.hold_by_arrow:
@@ -500,12 +399,15 @@ class MonoColumnParser:
 
 
 def load_mono_column(path: Path) -> Song:
-    # The vast majority of memo files you will encounter will be propely
-    # decoded using shift_jis_2004. Get ready for endless fun with the small
-    # portion of files that won't
-    with open(path, encoding="shift_jis_2004") as f:
-        lines = f.readlines()
+    files = load_files(path)
+    charts = [
+        _load_mono_column_file(lines)
+        for _, lines in files.items()
+    ]
+    return reduce(lambda a, b: a.merge(b), charts)
+    
 
+def _load_mono_column_file(lines: List[str]) -> Song:
     state = MonoColumnParser()
     for i, raw_line in enumerate(lines):
         try:
diff --git a/jubeatools/formats/jubeat_analyser/parser.py b/jubeatools/formats/jubeat_analyser/parser.py
new file mode 100644
index 0000000..a5ac351
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/parser.py
@@ -0,0 +1,124 @@
+"""Base class and tools for the different parsers"""
+from copy import deepcopy
+from .symbols import NOTE_SYMBOLS
+from decimal import Decimal
+from jubeatools.song import BPMEvent
+
+DIFFICULTIES = {1: "BSC", 2: "ADV", 3: "EXT"}
+
+SYMBOL_TO_DECIMAL_TIME = {
+    symbol: Decimal("0.25") * index for index, symbol in enumerate(NOTE_SYMBOLS)
+}
+
+
+class JubeatAnalyserParser:
+    def __init__(self):
+        self.music = None
+        self.symbols = deepcopy(SYMBOL_TO_DECIMAL_TIME)
+        self.current_beat = Decimal("0")
+        self.current_tempo = None
+        self.current_chart_lines = []
+        self.timing_events = []
+        self.offset = 0
+        self.beats_per_section = 4
+        self.bytes_per_panel = 2
+        self.level = 1
+        self.difficulty = None
+        self.title = None
+        self.artist = None
+        self.jacket = None
+        self.preview_start = None
+        self.hold_by_arrow = False
+        self.circle_free = False
+
+    def handle_command(self, command, value=None):
+        try:
+            method = getattr(self, f"do_{command}")
+        except AttributeError:
+            raise SyntaxError(f"Unknown analyser command : {command}") from None
+
+        if value is not None:
+            method(value)
+        else:
+            method()
+
+    def do_m(self, value):
+        self.music = value
+
+    def do_t(self, value):
+        self.current_tempo = Decimal(value)
+        self.timing_events.append(BPMEvent(self.current_beat, BPM=self.current_tempo))
+
+    def do_o(self, value):
+        self.offset = int(value)
+
+    def do_b(self, value):
+        self.beats_per_section = Decimal(value)
+
+    def do_pw(self, value):
+        if int(value) != 4:
+            raise ValueError("jubeatools only supports 4×4 charts")
+
+    do_ph = do_pw
+
+    def do_lev(self, value):
+        self.level = int(value)
+
+    def do_dif(self, value):
+        dif = int(value)
+        if dif <= 0:
+            raise ValueError(f"Unknown chart difficulty : {dif}")
+        if dif < 4:
+            self.difficulty = DIFFICULTIES[dif]
+        else:
+            self.difficulty = f"EDIT-{dif-3}"
+
+    def do_title(self, value):
+        self.title = value
+
+    def do_artist(self, value):
+        self.artist = value
+
+    def do_jacket(self, value):
+        self.jacket = value
+
+    def do_prevpos(self, value):
+        self.preview_start = int(value)
+
+    def do_bpp(self, value):
+        bpp = int(value)
+        if bpp not in (1, 2):
+            raise ValueError(f"Unexcpected bpp value : {value}")
+        elif self.circle_free and bpp == 1:
+            raise ValueError("#bpp can only be 2 when #circlefree is activated")
+        else:
+            self.bytes_per_panel = int(value)
+
+    def do_holdbyarrow(self, value):
+        self.hold_by_arrow = int(value) == 1
+
+    def do_holdbytilde(self, value):
+        if int(value):
+            raise ValueError("jubeatools does not support #holdbytilde")
+
+    def do_circlefree(self, raw_value):
+        activate = bool(int(raw_value))
+        if activate and self.bytes_per_panel != 2:
+            raise ValueError("#circlefree can only be activated when #bpp=2")
+        self.circle_free = activate
+
+    def define_symbol(self, symbol: str, timing: Decimal):
+        bpp = self.bytes_per_panel
+        length_as_shift_jis = len(symbol.encode("shift_jis_2004"))
+        if length_as_shift_jis != bpp:
+            raise ValueError(
+                f"Invalid symbol definition. Since #bpp={bpp}, timing symbols "
+                f"should be {bpp} bytes long but '{symbol}' is {length_as_shift_jis}"
+            )
+        if timing > self.beats_per_section:
+            message = (
+                "Invalid symbol definition conscidering the number of beats per section :\n"
+                f"*{symbol}:{timing}"
+            )
+            raise ValueError(message)
+        self.symbols[symbol] = timing
\ No newline at end of file
diff --git a/jubeatools/formats/memo/symbol.py b/jubeatools/formats/jubeat_analyser/symbol_definition.py
similarity index 98%
rename from jubeatools/formats/memo/symbol.py
rename to jubeatools/formats/jubeat_analyser/symbol_definition.py
index 195d4e2..41909f9 100644
--- a/jubeatools/formats/memo/symbol.py
+++ b/jubeatools/formats/jubeat_analyser/symbol_definition.py
@@ -1,5 +1,5 @@
 """
-Beat symbol definition
+Note symbol definition
 """
 from decimal import Decimal
 from typing import Optional, Tuple
diff --git a/jubeatools/formats/memo/mono_column/commons.py b/jubeatools/formats/jubeat_analyser/symbols.py
similarity index 96%
rename from jubeatools/formats/memo/mono_column/commons.py
rename to jubeatools/formats/jubeat_analyser/symbols.py
index 1aa89b7..84b64be 100644
--- a/jubeatools/formats/memo/mono_column/commons.py
+++ b/jubeatools/formats/jubeat_analyser/symbols.py
@@ -1,3 +1,5 @@
+"""Usual symbols for memo files"""
+
 NOTE_SYMBOLS = [
     "①",
     "②",
diff --git a/jubeatools/formats/memo/tests/__init__.py b/jubeatools/formats/jubeat_analyser/tests/__init__.py
similarity index 100%
rename from jubeatools/formats/memo/tests/__init__.py
rename to jubeatools/formats/jubeat_analyser/tests/__init__.py
diff --git a/jubeatools/formats/jubeat_analyser/tests/test_memo.py b/jubeatools/formats/jubeat_analyser/tests/test_memo.py
new file mode 100644
index 0000000..e85a0d8
--- /dev/null
+++ b/jubeatools/formats/jubeat_analyser/tests/test_memo.py
@@ -0,0 +1,15 @@
+from decimal import Decimal
+
+from hypothesis import given
+
+from jubeatools.song import BeatsTime, BPMEvent, Chart, Metadata, SecondsTime, Timing
+from jubeatools.testutils.strategies import NoteOption
+from jubeatools.testutils.strategies import notes as notes_strat
+
+from ..mono_column.dump import _dump_mono_column_chart
+from ..mono_column.load import MonoColumnParser
+
+
+@given(notes_strat(NoteOption.LONGS))
+def test_many_notes(notes):
+    ...
\ No newline at end of file
diff --git a/jubeatools/formats/memo/tests/test_mono_column.py b/jubeatools/formats/jubeat_analyser/tests/test_mono_column.py
similarity index 100%
rename from jubeatools/formats/memo/tests/test_mono_column.py
rename to jubeatools/formats/jubeat_analyser/tests/test_mono_column.py
diff --git a/jubeatools/formats/memo/tests/test_mono_column_hypothesis.py b/jubeatools/formats/jubeat_analyser/tests/test_mono_column_hypothesis.py
similarity index 64%
rename from jubeatools/formats/memo/tests/test_mono_column_hypothesis.py
rename to jubeatools/formats/jubeat_analyser/tests/test_mono_column_hypothesis.py
index bbfdf25..38a4be4 100644
--- a/jubeatools/formats/memo/tests/test_mono_column_hypothesis.py
+++ b/jubeatools/formats/jubeat_analyser/tests/test_mono_column_hypothesis.py
@@ -4,7 +4,9 @@ import hypothesis.strategies as st
 from hypothesis import given
 
 from jubeatools.song import BeatsTime, BPMEvent, Chart, Metadata, SecondsTime, Timing
-from jubeatools.testutils.strategies import long_note, tap_note
+from jubeatools.testutils.strategies import NoteOption, long_note
+from jubeatools.testutils.strategies import notes as notes_strat
+from jubeatools.testutils.strategies import tap_note
 
 from ..mono_column.dump import _dump_mono_column_chart
 from ..mono_column.load import MonoColumnParser
@@ -42,3 +44,21 @@ def test_single_long_note(note):
         parser.load_line(line)
     actual = set(parser.notes())
     assert set([note]) == actual
+
+
+@given(notes_strat(NoteOption.LONGS))
+def test_many_notes(notes):
+    timing = Timing(
+        events=[BPMEvent(BeatsTime(0), Decimal(120))], beat_zero_offset=SecondsTime(0)
+    )
+    chart = Chart(
+        level=0, timing=timing, notes=sorted(notes, key=lambda n: (n.time, n.position))
+    )
+    metadata = Metadata("", "", "", "")
+    string_io = _dump_mono_column_chart("", chart, metadata, timing)
+    chart = string_io.getvalue()
+    parser = MonoColumnParser()
+    for line in chart.split("\n"):
+        parser.load_line(line)
+    actual = set(parser.notes())
+    assert notes == actual
diff --git a/jubeatools/formats/memo/__init__.py b/jubeatools/formats/memo/__init__.py
deleted file mode 100644
index 5c3f116..0000000
--- a/jubeatools/formats/memo/__init__.py
+++ /dev/null
@@ -1,32 +0,0 @@
-"""
-memo is a vague term refering to several legacy formats.
-They were originally derived from the (somewhat) human-readable format choosen
-by websites storing official jubeat charts in text form as a memory aid.
-
-The machine-readable variants are partially documented (in japanese)
-on these pages :
-- http://yosh52.web.fc2.com/jubeat/fumenformat.html
-- http://yosh52.web.fc2.com/jubeat/holdmarker.html
-
-Known simple commands :
-  - b=<decimal>   : beats per measure (4 by default)
-  - m="<path>"    : music file path
-  - o=<int>       : offset in ms (100 by default)
-  - r=<int>       : increase the offset (in ms)
-  - t=<decimal>   : tempo
-  
-Known hash commands :
-  - #memo             # mono-column format
-  - #memo1            # youbeat-like but missing a lot of the youbeat features
-  - #memo2            # youbeat-like memo
-  - #boogie           # youbeat
-  - #pw=<int>         # number of panels horizontally (4 by default)
-  - #ph=<int>         # number of panels vertically (4 by default)
-  - #lev=<int>        # chart level (typically 1 to 10)
-  - #dif={1, 2, 3}    # 1: BSC, 2: ADV, 3: EXT
-  - #title="<str>"    # music title
-  - #artist="<str>"   # artist's name
-  - #jacket="<path>"  # music cover art path
-  - #prevpos=<int>    # preview start (in ms)
-  - #bpp              # bytes per panel (2 by default)
-"""
diff --git a/jubeatools/formats/memo/mono_column/__init__.py b/jubeatools/formats/memo/mono_column/__init__.py
deleted file mode 100644
index 688f4b7..0000000
--- a/jubeatools/formats/memo/mono_column/__init__.py
+++ /dev/null
@@ -1,2 +0,0 @@
-from .dump import dump_mono_column
-from .load import load_mono_column
diff --git a/jubeatools/song.py b/jubeatools/song.py
index 3d5cbe6..f3a0770 100644
--- a/jubeatools/song.py
+++ b/jubeatools/song.py
@@ -166,3 +166,23 @@ class Song:
     metadata: Metadata
     charts: Mapping[str, Chart] = field(default_factory=MultiDict)
     global_timing: Optional[Timing] = None
+
+    def merge(self, other: Song) -> Song:
+        if self.metadata != other.metadata:
+            raise ValueError(
+                "Merge conflit in song metadata :\n"
+                f"{self.metadata}\n"
+                f"{other.metadata}"
+            )
+        charts = MultiDict()
+        charts.extend(self.charts)
+        charts.extend(other.charts)
+        if (
+            self.global_timing is not None
+            and other.global_timing is not None
+            and self.global_timing != other.global_timing
+        ):
+            raise ValueError("Can't merge songs with differing global timings")
+        global_timing = self.global_timing or other.global_timing
+        return Song(self.metadata, charts, global_timing)
+
diff --git a/jubeatools/testutils/strategies.py b/jubeatools/testutils/strategies.py
index 001adc3..54f146f 100644
--- a/jubeatools/testutils/strategies.py
+++ b/jubeatools/testutils/strategies.py
@@ -94,7 +94,7 @@ def bad_notes(draw, longs: bool):
     note_strat = tap_note()
     if longs:
         note_strat = st.one_of(note_strat, long_note())
-    return draw(st.sets(note_strat))
+    return draw(st.sets(note_strat, max_size=50))
 
 
 @st.composite
@@ -105,7 +105,7 @@ def notes(draw, options: NoteOption):
     note_strat = tap_note()
     if NoteOption.LONGS in options:
         note_strat = st.one_of(note_strat, long_note())
-    raw_notes = draw(st.sets(note_strat))
+    raw_notes = draw(st.sets(note_strat, max_size=50))
 
     if NoteOption.COLLISIONS in options:
         return raw_notes
diff --git a/poetry.lock b/poetry.lock
index cb0295b..286976b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -72,7 +72,7 @@ description = "A library for property-based testing"
 name = "hypothesis"
 optional = false
 python-versions = ">=3.5.2"
-version = "5.16.3"
+version = "5.19.0"
 
 [package.dependencies]
 attrs = ">=19.2.0"
@@ -109,12 +109,12 @@ description = "A lightweight library for converting complex datatypes to and fro
 name = "marshmallow"
 optional = false
 python-versions = ">=3.5"
-version = "3.6.0"
+version = "3.6.1"
 
 [package.extras]
-dev = ["pytest", "pytz", "simplejson", "mypy (0.770)", "flake8 (3.7.9)", "flake8-bugbear (20.1.4)", "pre-commit (>=1.20,<3.0)", "tox"]
-docs = ["sphinx (3.0.3)", "sphinx-issues (1.2.0)", "alabaster (0.7.12)", "sphinx-version-warning (1.1.2)"]
-lint = ["mypy (0.770)", "flake8 (3.7.9)", "flake8-bugbear (20.1.4)", "pre-commit (>=1.20,<3.0)"]
+dev = ["pytest", "pytz", "simplejson", "mypy (0.770)", "flake8 (3.8.2)", "flake8-bugbear (20.1.4)", "pre-commit (>=2.4,<3.0)", "tox"]
+docs = ["sphinx (3.0.4)", "sphinx-issues (1.2.0)", "alabaster (0.7.12)", "sphinx-version-warning (1.1.2)", "autodocsumm (0.1.13)"]
+lint = ["mypy (0.770)", "flake8 (3.8.2)", "flake8-bugbear (20.1.4)", "pre-commit (>=2.4,<3.0)"]
 tests = ["pytest", "pytz", "simplejson"]
 
 [[package]]
@@ -217,7 +217,7 @@ description = "library with cross-python path, ini-parsing, io, code, log facili
 name = "py"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "1.8.1"
+version = "1.9.0"
 
 [[package]]
 category = "dev"
@@ -233,7 +233,7 @@ description = "pytest: simple powerful testing with Python"
 name = "pytest"
 optional = false
 python-versions = ">=3.5"
-version = "5.4.2"
+version = "5.4.3"
 
 [package.dependencies]
 atomicwrites = ">=1.0"
@@ -267,7 +267,7 @@ description = "Alternative regular expression module, to replace re."
 name = "regex"
 optional = false
 python-versions = "*"
-version = "2020.5.14"
+version = "2020.6.8"
 
 [[package]]
 category = "dev"
@@ -330,11 +330,11 @@ version = "3.7.4.2"
 
 [[package]]
 category = "dev"
-description = "Measures number of Terminal column cells of wide-character codes"
+description = "Measures the displayed width of unicode strings in a terminal"
 name = "wcwidth"
 optional = false
 python-versions = "*"
-version = "0.1.9"
+version = "0.2.5"
 
 [metadata]
 content-hash = "ea32264fbb53166d279acff6d1adda6bbf3892b58d1c1ccebe0efabd8b661959"
@@ -366,16 +366,16 @@ colorama = [
     {file = "colorama-0.4.3.tar.gz", hash = "sha256:e96da0d330793e2cb9485e9ddfd918d456036c7149416295932478192f4436a1"},
 ]
 hypothesis = [
-    {file = "hypothesis-5.16.3-py3-none-any.whl", hash = "sha256:7e8e0b7d412cb758c662dcbdcdc93cb8dccc38a9c67f2cd4bf885ba9f714f8d4"},
-    {file = "hypothesis-5.16.3.tar.gz", hash = "sha256:81f9a033900ea73c7b594173dbce7b9eb39222c04fc6278a6f33cc39c49b144a"},
+    {file = "hypothesis-5.19.0-py3-none-any.whl", hash = "sha256:dd21b1be951fefc9022047824c262f4e88d95dd24141b837b92e235c63baabb7"},
+    {file = "hypothesis-5.19.0.tar.gz", hash = "sha256:ba7c92006716aaee4684f7876c116adedcfb88b19fcb55d21c47b28f03f933bf"},
 ]
 isort = [
     {file = "isort-4.3.21-py2.py3-none-any.whl", hash = "sha256:6e811fcb295968434526407adb8796944f1988c5b65e8139058f2014cbe100fd"},
     {file = "isort-4.3.21.tar.gz", hash = "sha256:54da7e92468955c4fceacd0c86bd0ec997b0e1ee80d97f67c35a78b719dccab1"},
 ]
 marshmallow = [
-    {file = "marshmallow-3.6.0-py2.py3-none-any.whl", hash = "sha256:f88fe96434b1f0f476d54224d59333eba8ca1a203a2695683c1855675c4049a7"},
-    {file = "marshmallow-3.6.0.tar.gz", hash = "sha256:c2673233aa21dde264b84349dc2fd1dce5f30ed724a0a00e75426734de5b84ab"},
+    {file = "marshmallow-3.6.1-py2.py3-none-any.whl", hash = "sha256:9aa20f9b71c992b4782dad07c51d92884fd0f7c5cb9d3c737bea17ec1bad765f"},
+    {file = "marshmallow-3.6.1.tar.gz", hash = "sha256:35ee2fb188f0bd9fc1cf9ac35e45fd394bd1c153cee430745a465ea435514bd5"},
 ]
 more-itertools = [
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@@ -440,42 +440,42 @@ pluggy = [
     {file = "pluggy-0.13.1.tar.gz", hash = "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0"},
 ]
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-    {file = "py-1.8.1.tar.gz", hash = "sha256:5e27081401262157467ad6e7f851b7aa402c5852dbcb3dae06768434de5752aa"},
+    {file = "py-1.9.0-py2.py3-none-any.whl", hash = "sha256:366389d1db726cd2fcfc79732e75410e5fe4d31db13692115529d34069a043c2"},
+    {file = "py-1.9.0.tar.gz", hash = "sha256:9ca6883ce56b4e8da7e79ac18787889fa5206c79dcc67fb065376cd2fe03f342"},
 ]
 pyparsing = [
     {file = "pyparsing-2.4.7-py2.py3-none-any.whl", hash = "sha256:ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b"},
     {file = "pyparsing-2.4.7.tar.gz", hash = "sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1"},
 ]
 pytest = [
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-    {file = "pytest-5.4.2.tar.gz", hash = "sha256:eb2b5e935f6a019317e455b6da83dd8650ac9ffd2ee73a7b657a30873d67a698"},
+    {file = "pytest-5.4.3-py3-none-any.whl", hash = "sha256:5c0db86b698e8f170ba4582a492248919255fcd4c79b1ee64ace34301fb589a1"},
+    {file = "pytest-5.4.3.tar.gz", hash = "sha256:7979331bfcba207414f5e1263b5a0f8f521d0f457318836a7355531ed1a4c7d8"},
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 python-constraint = [
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 ]
 rope = [
     {file = "rope-0.17.0.tar.gz", hash = "sha256:658ad6705f43dcf3d6df379da9486529cf30e02d9ea14c5682aa80eb33b649e1"},
@@ -551,6 +551,6 @@ typing-extensions = [
     {file = "typing_extensions-3.7.4.2.tar.gz", hash = "sha256:79ee589a3caca649a9bfd2a8de4709837400dfa00b6cc81962a1e6a1815969ae"},
 ]
 wcwidth = [
-    {file = "wcwidth-0.1.9-py2.py3-none-any.whl", hash = "sha256:cafe2186b3c009a04067022ce1dcd79cb38d8d65ee4f4791b8888d6599d1bbe1"},
-    {file = "wcwidth-0.1.9.tar.gz", hash = "sha256:ee73862862a156bf77ff92b09034fc4825dd3af9cf81bc5b360668d425f3c5f1"},
+    {file = "wcwidth-0.2.5-py2.py3-none-any.whl", hash = "sha256:beb4802a9cebb9144e99086eff703a642a13d6a0052920003a230f3294bbe784"},
+    {file = "wcwidth-0.2.5.tar.gz", hash = "sha256:c4d647b99872929fdb7bdcaa4fbe7f01413ed3d98077df798530e5b04f116c83"},
 ]
diff --git a/pyproject.toml b/pyproject.toml
index 36b11ba..9cab35e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,6 +28,14 @@ isort = "^4.3.21"
 [tool.poetry.scripts]
 jubeatools = 'jubeatools.cli:convert'
 
+[tool.isort]
+multi_line_output = 3
+include_trailing_comma = true
+force_grid_wrap = 0
+use_parentheses = true
+ensure_newline_before_comments = true
+line_length = 88
+
 [build-system]
 requires = ["poetry>=0.12"]
 build-backend = "poetry.masonry.api"