Mujitsu and Tairaku's Shakuhachi BBQ

Can anyone identify these characters? Painted in urushi below the utaguchi of an old 1.9 with a very shallow (Shinku Dan-like) utaguchi:

Utaguchi (mouthpiece, literally 'song mouth'). 22mm inside opening, 36mm outside width, almost perfectly round. Very shallow dip at the inlay. Inlay base is 13mm, top is 10mm. Utaguchi facet is more perpendicular to the body than modern shakuhachi. Meri notes seem to be achieved easily. Very shallow top angle toward chin-rest, almost cut straight. Chin rest is rounded.