| Issue | Why It Happens | How to Fix | |-------|----------------|-------------| | | Wrong encoding or font embedding | Open in Adobe Acrobat Reader → File → Properties → Fonts → Install missing Japanese fonts (e.g., MS Mincho, Yu Gothic) | | Pages are upside down or skewed | Bad scan from a physical book | Use ScanTailor or Briss to auto-rotate and crop each page | | Audio buttons don’t work | Interactive features stripped from unofficial PDF | Download separate MP3s from Gakushudo’s official site (if available) or use a text-to-speech tool like Voicepedia | | Kanji missing furigana | OCR error during PDF conversion | Re-OCR using ABBYY FineReader or free tool Tesseract with Japanese language pack |
Go to File → Print → Select "Adobe PDF" as the printer. This redraws the entire document. This single trick solves 80% of issues because it flattens the problematic layers into a static image-text hybrid. gakushudo n4 pdf fix
