Cipher methods Symbols
Ninjargon (ninja alphabet)
Ninjargon is a fictional pictographic alphabet popularised by puzzle books and tabletop RPGs of the 2000s-2010s, on the ninja theme (medieval Japanese shinobi). Glyphs are angular, sharp shapes evoking traditional weapons: shuriken (4-to-6-pointed stars), katana (curved blades), kunai (daggers), bo (staffs). It is not an authentic Japanese script — it is a Western pop-culture invention on the ninja theme, in the same vein as the ‘pirate’ or ‘viking’ alphabets of puzzle anthologies.
The alphabet has been used in particular within the Naruto franchise (with no canonical link: it is a fan-made appropriation), in the board game Way of the Ninja (Asmodee, 2014), and in several Detective Academy puzzle books (Disney Hyperion, 2010s).
How does the alphabet work?
The cipher uses a monoalphabetic substitution: every letter of the plaintext is replaced by a glyph drawn from a fixed correspondence table. It is one of the oldest cryptographic techniques on record — already described in antiquity (Caesar cipher, ~50 BC) — and the most directly readable family for a beginner.
The table holds 26 glyphs for the 26 Latin letters + 10 digits. The glyphs are angular shapes inspired by ninja weapons: stars, blades, crossed lines.
Cryptographic strength: weak. Because every plaintext letter always maps to the same glyph, the cipher falls to a frequency analysis in a few dozen words (in both English and French, E remains the most common letter, an immediate entry point). Monoalphabetic substitutions are therefore used today for their decorative, playful or pedagogical value — not to protect real information.
Historical and modern usage
- 2000s-2010s puzzle books — Detective Academy, Sleuth Investigators.
- Tabletop RPGs — Way of the Ninja, Shinobi Saga.
- Naruto fan community — fan-made, non-canonical appropriations.
- Pedagogy — example of themed pop-culture cryptography for children’s puzzles.
Related variants
- Klingon (pIqaD) — see our entry, another angular fictional alphabet.
- Daedric — see our entry, another fictional runic alphabet.
What are the weaknesses?
- Monoalphabetic substitution — immediate frequency analysis.
- Documented alphabet — public table on dCode and in puzzle anthologies.
- No digits in some sources — dCode ships 10 digits which we expose here.
The 26 glyphs
The 10 digits
