I must be simple, but cannot see anything difficult about that that 'Japanese' compass:
Seems a nice & simple wheeze to read off degrees in 100's and just add on up to 100 more off the detailed scale, which gives one's heading.
Makes the usual but unwieldy lumps of 90's into a a familiar transcription - assuming Japanese schools used arabic numerals and denary maths.
Happy Christmas,
mike hallam (West Sussex)
- BTW got the 80 hp Rans S6-116 airborne off the soft grass here today to successfully trial my kid's present to me, a pair of low pressure 'Tundra' tyres, fitted last w/end