All of it

This is every sword plotted by length, with a high level confirmation… with the limit of a few o-dachi over 135cm. Just over 15,000.

Only about 10 years of work to get to that.

You can see various trends in here, the higher level papers show a clear ramp up in upper length (more ubu tachi present). The upper limit of wakizashi length shows clustering and we can see the longer wakizashi fall off the map when it gets to higher papers. Overall the strong visual signal for long swords shows that there is a clear preference for use in this range, and swords longer than about 78cm exist almost in a desert, they are so rare compared to the strongly defined standard length range.


I’ve been working on some tools to visualize data and see if the patterns allow for some new insights, or at least to confirm anecdotal evidence or gut level knowledge.

This below is a chart of sword lengths vs. year of production for all Juyo Token, Tokubetsu Juyo Token and Juyo Bijutsuhin swords. I cut the length off at 150 cm, as there are a scattering of outlier swords (odachi and onaginata) that will cause the chart to compress.

Anyway you should be able to look at this image and draw a few conclusions. What do you see?

Analysis after the break…

Continue reading Visualization

Honami Origami and Valuations

Some time ago I had a Fukuoka Ichimonji katana with a Honami Kochu origami that stated a value of 100 gold pieces for the blade. I did not think too heavily about it. A dealer from Japan happened to see the blade and pointed out the paper and he said “That valuation is very unusual, I never saw one like that.”

I thought for some years he was referring to the fact that it had a value on it at all, as I was mostly familiar with later Honami origami that didn’t have any value on them. Recently I encountered another one like this, and so I decided to look at whatever records I could find about Honami valuations and try to dig more deeply into the subject.

Continue reading Honami Origami and Valuations