- Kinko-ryu - old - Vintage were made before and soon after World War 2.
Tozan - Vintage were made before and soon after World War 2.
- Tend to have a narrower bore and a "reedier" tone.
http://reibo.org/oldshaks.html For playing sankyoku (gaikyoku), Kinko-ryu honkyoku, or Koten honkyoku, old flutes are recommended.
http://reibo.org/oldshaks.html For playing Doukyoku, however, modern shakuhachi are advisable, though with extra effort one can certainly use an old shakuhachi. This is because Doukyoku is technically more demanding than other styles of honkyoku: the pieces demand rapid changes in embouchure and blowing position (meri/kari) along with fast fingerings, plus there are certain note combinations that are much easier to play on shakuhachi made by the contemporary maker Miura Ryuho than on other shakuhachi, even modern ones, hence the popularity of his flutes among serous Doukyoku players. That said, I play Doukyoku on my old 1.8, and would buy an old 2.1, 2.4, or 2.7 if I could find one.
http://reibo.org/oldshaks.html Many old shakuhachi have one or more notes that will break or warble if pushed hard.