Tanaka and other Japaese irons

Hi all, am educating myself about Japanese golf clubs, mainly irons and know how good Miura, Vega, Honma, Epon, etc are. I have found a set of irons by Tanaka but can find NO info at all about these on-line ? I suspect they aren't quality forged irons as this set has Apollo shafts fitted ? (Not exactly top dollar ?) btw did you know Miura forged several models of heads for both TaylorMade and Titleist in the past ?

Any info gladly welcomed ?

thanks Roberta