Is there a book where Choki Motobu shows his 12 drills? I thought there was. Is it "Karate My Art"?
try this one: https://www.amazon.com/Okinawan-Kempo-Choki-Motobu/dp/092012917X/
I first baught the hardback version of this book (only 2000 hardback copies printed; each with its own certificate) in the 1990s. They since published a much cheaper paperback version :-) https://www.amazon.co.uk/Okinawan-Kempo-Choki-Motobu/dp/092012917X/ (same one that Holger has linked to above).
This is the exact same book translated by different people (slightly better photos): https://www.amazon.co.uk/Karate-Jutsu-Kumite-Motobu-Choki/dp/1986139034/
I hope that helps.
All the best,
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