Mujitsu and Tairaku's Shakuhachi BBQ

I have two older flutes, one is a single piece, 1.9 rust in color and with a myoan style ivory utaguchi and the makers stamp says Tsuki Oka (moon over hill I believe). At the blowing end it has a Tori gate stamped on the bottom side and where the root end is filed there is a hillside landscape and a moon over it all done with fine file work. Also, next to the makers stamp there is writing which I understand says -- very special made. It is a very beautiful flute and I would like to know more about it but can find nothing with that makers name.
  The other flute is a two piece, 1.8 tozan flute which is very thick and amber in color with a black root end. It has a very small opening at the root end and takes very little breath to sound. I find that I have to play it quite differently from my other flutes but feel it makes a good old man flute as it requires less breath. It is signed Kyosen I believe. I have found  translations of Kyosen as small hole and great river among other things. I would like to know more about why the small opening and understand why this style of flute is so out of favor. It can be both loud and breathy despite the small opening. Any thoughts would be appreciated.
  I don't know how to attach pictures but if you were to email me I could send photos of either flute.