How to Fix Garbled Japanese Text (文字化け) in CSV Files: Complete Guide

8 min read

Working with Japanese text in CSV files often leads to garbled characters (文字化け, mojibake). This comprehensive guide will show you how to fix these encoding issues and ensure your Japanese text displays correctly.

What Causes Garbled Japanese Text?

Japanese text becomes garbled when there's a mismatch between:

Common Scenarios Where Japanese Text Gets Garbled

Example of Garbled Text:

Original Japanese: 東京都渋谷区
Garbled Display: æ±äº¬éƒ½æ¸‹è°·åŒº
After Fixing: 東京都渋谷区

Method 1: Using Excel's Save As (Basic Solution)

  1. Open your CSV file in Excel
  2. Click File → Save As
  3. Choose CSV UTF-8 (*.csv) from the format dropdown
  4. Save the file

Pros: Simple, no tools needed
Cons: Doesn't always work, especially with mixed encodings

Method 2: Using Text Editors

  1. Open the file in a text editor that supports encoding conversion (like Notepad++)
  2. Convert from Shift-JIS to UTF-8
  3. Save the file

Pros: Free, more control over the process
Cons: Can be technical, risk of damaging CSV structure

Method 3: Using Our Japanese CSV Fixer (Recommended)

For a reliable and automated solution, use our Japanese CSV Encoding Fixer:

  1. Upload your CSV file with garbled Japanese text
  2. Our system automatically detects the source encoding
  3. Preview the fixed text instantly
  4. Download your corrected UTF-8 CSV file

Common Japanese CSV Encoding Problems

1. Excel Export Issues

Japanese versions of Excel often default to Shift-JIS encoding. When these files are opened in non-Japanese systems, the text appears garbled.

2. Web Application Downloads

Many Japanese web applications export CSV files in Shift-JIS, but modern web browsers expect UTF-8.

3. Mixed Encoding Issues

Files containing both Japanese and Western text can end up with mixed encodings, especially when data is copied from different sources.

Best Practices for Japanese CSV Files

  1. Always specify the encoding when reading/writing CSV files
  2. Use UTF-8 as your standard encoding format
  3. Include a BOM (Byte Order Mark) for Excel compatibility
  4. Test with a small sample before processing large files

Code Examples

Python Solution (Manual Method)

import pandas as pd

# Read CSV with Japanese encoding
df = pd.read_csv('input.csv', encoding='shift-jis')

# Save as UTF-8
df.to_csv('output.csv', encoding='utf-8-sig')  # -sig adds BOM for Excel

FAQ About Japanese CSV Encoding

Q: Why does Excel show Japanese characters as squares?

This usually happens when Excel doesn't recognize the encoding or when the system lacks Japanese language support.

Q: Will fixing the encoding affect non-Japanese text?

No, proper encoding conversion preserves all characters, including English text, numbers, and special characters.

Q: How can I prevent encoding issues in the future?

Always save CSV files in UTF-8 format and specify the encoding when working with files programmatically.

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