He is most definitely a great of the Bantamweight division! I don't know what you're referring to.
Eh, I'm not going to get into the ins & outs of how guilty Nery is for being a steroid-cheating motherfucker, but it's laughable to call Yamanaka great. He was a very good fighter who was never, ever great.
Stack 'em up: Eder Jofre, Ruben Olivares, Manuel Ortiz, Panama Al Brown, Carlos Zarate, Lupé Pintor, Veeraphol Sahaprom/Nakornluang-Promotion, Johnny Tapia, Orlando Canizales, Jeff Fenech, Fighting Harada. These guys were bantamweight greats (or, you know, in a couple cases "greats who fought at bantamweight").
Yamanaka never beats any of them, ever.
Israel Contreras, Adolfo Zamora, Poison Junior Jones, Miguel Lora, Wilfredo Vazquez, Rafael Marquez, Timmy Austin, Khaokor Galaxy, Jhonny Gonzalez, Rodolfo Martinez, Sung-kil Moon, Nana Konadu, Abner Mares, Hozumi Hasegawa, Fernando Montiel, Joichiro Tatsuyoshi, Daniel Zaragoza...
All very good fighters, & not great. I think that I'd take every single one of them over Yamanaka, too.
We're talking about a division that goes back over one hundred years. Having a nice left cross & cool Animé-style hair does not greatness bestow in such company.
PS: Also, though he never won a title in this division, Toshiaki Nishioka was three or four times the southpaw Japanese counterpuncher that Yamanaka was, & head-to-head would stand Yamanaka completely on his head without any trouble whatsoever.
What does that make Nishioka, if you call Yamanaka a "great"? Super-duper great?
I'm not one of those curmudgeons who thinks language should never evolve, but to call Yamanaka anything approaching "great" is hyperbole, plain & simple.
PPS: Apart from SY's hair. His hair/'tache combo was truly great. Not as great as say Gushiken's Japfro/Imperial combo, but still, great.