Run · Voynich Manuscript

T40 rung A, planted control: key recovery with the true sign boundaries

The setting is the best Herbal A draw of T39 round 1. Rung A says the fitted family is not intrinsically unbreakable; what limits it is finding where one sign ends and the next begins.

Partly passes: the key is largely recoverable when the boundaries are known (held-out decode '...sce mpesr ibusme a ... risior e u a smon t iusex e...' for '...in campestribus melior autem ... crispiora quae in montibus excepti...'), but coverage stays below the bar300k iterations: 0.627 / 0.634 / 0.294 (0.697); 1.5M iterations: 0.706 / 0.728 / 0.336 (0.697)0

Result

Run	Measured	Result	Against	Decision	Date
Run	Held-out key accuracy by use / character similarity to the true plaintext / dictionary coverage (true plaintext's)	300k iterations: 0.627 / 0.634 / 0.294 (0.697); 1.5M iterations: 0.706 / 0.728 / 0.336 (0.697)	Protocol bar: 70 % of the plaintext's dictionary coverage (0.49) or 50 % word accuracy	Partly passes: the key is largely recoverable when the boundaries are known (held-out decode '...sce mpesr ibusme a ... risior e u a smon t iusex e...' for '...in campestribus melior autem ... crispiora quae in montibus excepti...'), but coverage stays below the bar

What it used and found

Crack attempt on Herbal A under the fitted period-cipher setting

Method

MTH

Latin genre texts

Dataset

DAT

Naibbe cipher tables and example plaintexts (greshko/naibbe-cipher, commit 719f2f4c)

Dataset

DAT

ZL3b transcription

Dataset

DAT

Latin as a re-spaced homophonic stream (period practices)

Answer it tests

ANS

Parameters

pages = Herbal A, training / held-out per D-HERBAL-SPLIT, setting = {'K': 50, 'h_c': 4, 'h_v': 1, 'lam': 0.5, 'Ssyl': 0, 'abbrev': 0, 'p_copy': 0.3, 'p_stay': 0.9, 'window': 5, 'novowel': 0, 'p_break': 0.5, 'spacing': 'stream', 'simplify': 1}, plaintext = Pliny NH 16, iterations = [300000, 1500000]

Cite it

Mysteries Department. (2026). T40 rung A, planted control: key recovery with the true sign boundaries [Run RUN0DCBBPFSJ189]. https://mysteriesdept.com/r/RUN0DCBBPFSJ189

@misc{mysteriesdept_run0dcbbpfsj189,
  title     = {T40 rung A, planted control: key recovery with the true sign boundaries},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Run, catalog key RUN0DCBBPFSJ189},
  url       = {https://mysteriesdept.com/r/RUN0DCBBPFSJ189}
}