What's interesting about keirin frames from Japan is that the Japanese were practically infatuated with Italian designs from the 70's or so, and those are the specs that tended to get locked down. Just look at the bikes -- lugged, steep angles, rather tight clearances (even by track standards), higher bottom brackets, low trail, standard tubing diameters, you name it. At the time you couldn't tell a keirin frame from a good Italian one, but of course Italy has moved on and Japan hasn't as much. It'll be interesting to see keirins raced on disc wheels this year, and approval for carbon frames in keirin in the works.