Atbash is a substitution cipher: each letter is replaced by its mirror in the alphabet (A↔Z, B↔Y, C↔X, …). The substituted letters are then evaluated — in our implementation, under the Jewish (Hebrew Standard) values.
Mirror substitution (A ↔ Z) · sum under Jewish valuesAbout this cipher
Atbash is older than most gematria — it appears in the Book of Jeremiah, where 'Sheshakh' (שֵׁשַׁךְ) is the Atbash substitution of 'Bavel' (בבל / Babylon). It's the canonical biblical example of letter-substitution as cryptography.
For English input, evaluating Atbash under ordinal-position alone produces the same number as Reverse Ordinal (since the mirror of position p is position 27 − p). To keep Atbash genuinely distinct in our calculator, we evaluate the substituted letters under our Jewish-value table — preserving the conceptual spirit of 'substitute, then evaluate under Hebrew Standard'.
Worked example
Input: ABC
Result: 1200
A → Z (500), B → Y (400), C → X (300). 500 + 400 + 300 = 1200. Digital root: 1 + 2 + 0 + 0 = 3.
Frequently asked
Is Atbash a cipher or a gematria method?
Both. Originally it's a substitution cipher (mirror letter for letter); as a gematria technique you substitute, then sum the substituted letters' values under some other method.
Why does GeMater's Atbash use Jewish values?
On English-only ordinals, Atbash (mirror + sum positions) is mathematically equivalent to Reverse Ordinal. We evaluate the mirrored letters under our Jewish-value table so Atbash stays a distinct number — and so it stays conceptually close to the classical Hebrew technique.
What's the most famous example of Atbash?
Sheshakh (שֵׁשַׁךְ) in Jeremiah 25:26 is the Atbash of Bavel (בבל / Babylon) — a biblical cryptogram.