Looks I was right on the Japan call. These Japanese makers could stamp any brand name on them you wanted, so it's difficult sometimes to nail down the exact source. They could have been stamped for a chain store like HF, department store or auto parts store chains, or for a west coast wholesale jobber who would then sell them to other chains or mom-and-pops. They could have even been made for the tool telemarketing or mail order trades. They could be a one-off where only a single entire production run was ever labeled like this. Fuller is a brand that comes to mind reminiscent of these wrenches and era. I believe they are decent wrenches and should serve the homeowner or DIYer just fine.