pbw

Hi. Can someone tell me what 'PBW' means on a japanese blade? Thanks

Hi. have a blue and a green, black handled set of blades. They are stamped PBW and JTTAA and are made by the Nakakura Company. There is a japanese styled cream coloured circle painted on one of the handles, with a smaller red circle inside this, with some black writing which looks like 'er' or...