Recently, I’ve been revisiting the Voynich Manuscript’s Quire 20 (‘Q20’) with AI assist from Anthropic’s Claude. The idea is to look at specific Voynichese behaviours in close detail, to see if there’s anything to be found there, however small.
One of the most visually intriguing features is known to Voynich researchers as “Neal Keys”. I remember Philip Neal first describing this to me about 15 years ago (as I recall) at one of the London Voynich pub meets I used to run. So… what’s the latest update on this?
Horizontal Neal Keys
I last posted here about single-leg gallows back in 2020. Briefly, the top line of Voynich paragraphs is known as a “Tiltman line” (in honour of WWII code-breaker Brigadier John Tiltman, who had a particular interest in the Voynich Manuscript), because of its unusual properties. For example, it’s the most common place to find words containing single-leg gallows (EVA p/f), aside from the (separately anomalous) first word of a paragraph.
Philip Neal further pointed out that non-paragraph-initial words on the first line of a paragraph containing single-leg gallows are often adjacent to each other: though I calculated the raw probability of two being adjacent as 2.7%, while the actual probability is 5.4%. So this “Neal Key” behaviour is definitely a thing, though perhaps not quite as big a thing as it at first seemed.
This was the context for revisiting the topic with Claude to hand. The AI analysis proved very similar (feel free to replicate the same exercise):
- For first-line pairs of p/f-words, there’s no particular preference for pairs (as opposed to singletons or triplets)
- However, they do tend to cluster more than k-words or t/k-words taken together
- The left key of an adjacent p/f-word first-line pair ends in -dy unusually often (41% vs 32% expected for p/f-words generally, or 26% for all top-line words)
- The right key of an adjacent p/f-word first-line pair starts o- or qo- 61% of the time (52% expected)
- Yet even so, the preference for clustering isn’t explained by Currier’s dy…qo word adjacency behaviour.
Why might this be so? I spent some time exploring the hypothesis that this might be a modal behaviour – i.e. that something on a top line triggers a “behaviour mode” where p/f-words are far more likely to happen than in other modes. As possible support for this, Claude notes that p/f-words on top lines are the only feature whose type persisted across intervening words.
To explore this more, I prompted Claude to assess whether Voynichese had any other similar modal behaviours, that would yield other glyphs or patterns of glyphs to cluster in a similar way. (Note that I was only looking at Q20, rather than the whole manuscript.) Here are some of the more modal / clustery behaviours it suggested, though note that these were all for lines with word 1, word 2 and the line-final word excluded:
- Top lines: [qot- qot-] 22 matching lines found (13–15 expected)
- Non-top lines: [word-containing-t word-containing-t word-containing-t]: 41 matching lines found (26 expected)
- Non-top lines: [ot- ot-] 67 found (vs 52 expected) [though this is similar to the word-containing-t triplet result]
Generally, though, aside from this slight clustering of t-words, nothing else really behaved like p/f-words on Tiltman lines. An initial p made no difference to how many p/f-words the top line had, but they tended to turn up about a word earlier.
Another thing of possible interest was that in top lines not starting with p/f, the words before the first p/f-word included an -ar-final word about a third of the time, against about one in seven in comparable stretches of unkeyed top lines, dropping back to normal after the key. (Though Claude does flag that this was not a very strong signal.)
So, What Do You Make Of All That, Then?
Tiltman was right to point out that the topmost lines of paragraphs behave anomalously: and Philip Neal was also right to note that p/f-words ‘stick together like birds of a feather’ (my words, not his), particularly in Q20. (It’s actually largely true throughout the Voynich Manuscript, though that’s an analysis for another day.)
But on balance, the p/f-word behaviour still seems to me to be arguably more modal than key-like: the fact that it’s restricted so tightly to top lines is perhaps a giveaway that something odd is going on. And even though the way words containing t cluster is less obviously remarkable, it’s hard to exclude the possibility that it’s part of the same broader mechanism, even if we can’t quite see what it is.
I think the good news from this, though, is that trying to draw conclusions and running them past Claude does help keep you honest: any inconsistency between the responses and your summaries gets quickly exposed and ripped apart. (Which I think is a good thing.)
Claude is still very local-minded, and you have to push quite hard to get it to evaluate different hypotheses. But that’s probably a good thing, all in all: genuinely hard work remains devilishly hard, even with AI on your side.












