diff --git a/tja2fumen/tja2fumen.py b/tja2fumen/tja2fumen.py
index 20771da..05f6adb 100644
--- a/tja2fumen/tja2fumen.py
+++ b/tja2fumen/tja2fumen.py
@@ -2,6 +2,8 @@ import os
 import sys
 import struct
 import argparse
+from copy import deepcopy
+from parsetja import parseTJA
 
 tja2fumen_version = "v0.1"
 
@@ -416,6 +418,109 @@ def checkMismatchedBytes(file1, file2):
     return incorrect_bytes
 
 
+TJA_NOTE_TYPES = {
+    '1': 'Don',
+    '2': 'Ka',
+    '3': 'DON',
+    '4': 'KA',
+    '5': 'Drumroll',
+    '6': 'DRUMROLL',
+    '7': 'Balloon',
+    '8': 'EndDRB',
+    '9': 'Kusudama',
+    'A': 'DON',  # hands
+    'B': 'KA',   # hands
+}
+
+# Filler metadata that the `writeFumen` function expects
+default_note = {'type': '', 'pos': 0.0, 'item': 0, 'padding': 0.0,
+                'scoreInit': 0, 'scoreDiff': 0, 'durationPadding': 0.0}
+default_branch = {'length': 0, 'padding': 0, 'speed': 1.0}
+default_measure = {
+    'bpm': 0.0,
+    'fumenOffset': 0.0,
+    'gogo': False,
+    'hidden': False,
+    'padding1': 0,
+    'branchInfo': [-1, -1, -1, -1, -1, -1],
+    'padding2': 0,
+    'normal': deepcopy(default_branch),
+    'advanced': deepcopy(default_branch),
+    'master': deepcopy(default_branch)
+}
+
+
+def convertTJAToFumen(fumen, tja):
+    # Fumen offset for the first measure that has a barline
+    fumenOffset1 = float(tja['metadata']['offset']) * -1000
+
+    # Variables that will change over time due to events
+    currentBPM = 0.0
+    currentGogo = False
+    currentHidden = False
+    currentBranch = 'normal'  # TODO: Program in branch support
+
+    # Parse TJA measures to create converted TJA -> Fumen file
+    tjaConverted = { 'measures': [] }
+    for i, measureTJA in enumerate(tja['measures']):
+        measureFumenExample = fumen['measures'][i+9]
+        measureFumen = deepcopy(default_measure)
+
+        # TODO Event: GOGOTIME
+
+        # TODO Event: HIDDEN
+
+        # TODO Event: BARLINE
+
+        # TODO Event: MEASURE
+
+        # Event: BPMCHANGE
+        # TODO: Handle TJA measure being broken up into multiple Fumen measures due to mid-measure BPM changes
+        midMeasureBPM = [(0, currentBPM)]
+        for event in measureTJA['events']:
+            if event['name'] == 'bpm':
+                currentBPM = float(event['value'])
+                if event['position'] == 0:
+                    midMeasureBPM[0] = (0, currentBPM,)
+                else:
+                    midMeasureBPM.append((event['position'], currentBPM))
+        if len(midMeasureBPM) > 1:
+            test = None
+        measureFumen['bpm'] = currentBPM
+
+        # TODO: `measureFumen['fumenOffset']
+        #       Will need to account for BARLINEON and BARLINEOFF.
+        #       Some examples that line up with actual fumen data:
+        # fumenOffset0 = (fumenOffset1 - measureLength)
+        # fumenOffset2 = (fumenOffset1 + measureLength)
+        measureLength = 240_000 / currentBPM
+        # measureFumen['fumenOffset'] = prev['fumenOffset'] + measureLength
+
+        # Create note dictionaries based on TJA measure data (containing 0's plus 1/2/3/4/etc. for notes)
+        note_counter = 0
+        for i, note_value in enumerate(measureTJA['data']):
+            if note_value != '0':
+                note = deepcopy(default_note)
+                note['pos'] = measureLength * (i / len(measureTJA['data']))
+                note['type'] = TJA_NOTE_TYPES[note_value]  # TODO: Handle BALLOON/DRUMROLL
+                note['scoreInit'] = tja['scoreInit']  # Probably not fully accurate
+                note['scoreDiff'] = tja['scoreDiff']  # Probably not fully accurate
+                measureFumen[currentBranch][note_counter] = note
+                note_counter += 1
+        measureFumen[currentBranch]['length'] = note_counter
+
+        # Append the measure to the tja's list of measures
+        tjaConverted['measures'].append(measureFumen)
+
+    tjaConverted['headerUnknown'] = b'x\00' * 80
+    tjaConverted['order'] = '<'
+    tjaConverted['length'] = len(tjaConverted['measures'])
+    tjaConverted['unknownMetadata'] = 0
+    tjaConverted['branches'] = False
+
+    return tjaConverted
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(
         description="tja2fumen {0}".format(tja2fumen_version)
@@ -483,12 +588,28 @@ if __name__ == "__main__":
     if len(sys.argv) == 1:
         parser.print_help()
     else:
-        arguments = parser.parse_args()
-        inputFile = getattr(arguments, "file_m.bin")
-        parsedSong = readFumen(inputFile, arguments.order, arguments.debug)
-        outputName = inputFile.name.split('.')[0] + "_rebuilt.bin"
-        outputFile = open(outputName, "wb")
-        writeFumen(outputFile, parsedSong)
-        # Read output file back in to validate that the rewritten song is a perfect match
-        inputFileOut = open(outputName, "rb")
-        print(checkMismatchedBytes(inputFile.name, outputFile.name))
+        # arguments = parser.parse_args()
+        arguments = {
+            "input_fumen": "./roku/ia6cho_m.bin",                        # NB: Contains only oni chart
+            "input_tja": "./roku/Rokuchounen to Ichiya Monogatari.tja",  # NB: Contains 5 charts
+        }
+        # Parse fumen
+        inputFile = open(arguments["input_fumen"], "rb")
+        parsedSongFumen = readFumen(inputFile)
+
+        # Steps to validate the `writeFumen` function to make sure it reproduces correct output
+        validate = False
+        if validate:
+            outputName = inputFile.name.split('.')[0] + "_rebuilt.bin"
+            outputFile = open(outputName, "wb")
+            writeFumen(outputFile, parsedSongFumen)
+            # Read output file back in to validate that the rewritten song is a perfect match
+            print(False if checkMismatchedBytes(inputFile.name, outputFile.name) else True)
+
+        # Parse tja
+        inputFile = open(arguments["input_tja"], "r", encoding="utf-8-sig")
+        parsedSongsTJA = parseTJA(inputFile)
+
+        # Try converting the Oni TJA chart to match the Oni fumen
+        convertedTJA = convertTJAToFumen(parsedSongFumen, parsedSongsTJA['Oni'])
+        # writeFumen(outputFile, convertedTJA)