There is also another study that since koma-jaku, which was introduced from the Kingdom of Goryeo and 2 shaku larger than the da-chi, was spread before the Taiho Ritsuryo in Japan; the da-chi of Tang became sho-shaku.
ただし異説もあり、日本には大宝令以前に高麗から渡来した大尺より2尺長い高麗尺が普及していたので、これが大宝令の大尺とされ、唐の大尺が小尺にされたともいう。