I believe this item is from the late Showa to early Heisei period. Although there is no Yamanaka lacquerware mark, the ingredient label inside (photo 8) has the approval number "SK-IK-1025," which I researched and found to be a product of Kihachi Kobo. I have taken out 5 lids and 1 bowl from the wrapping for photography (inside the wrapping, there are 5 bowls at the bottom and 5 lids stacked on top). I would appreciate it if you could refrain from price negotiations. #sui255byjtVintage