In 2025, a friend of mine submitted a Shonai ichibu to PCGS that came back as "Counterfeit Altered Variety," indicating that the host coin was real but the Shonai stamps were countefeit. Upon closer inspection, not only did its stamps match my Shonai example exactly, but they matched most examples I've seen. He contacted the seller and found out they were no longer selling Shonai ichibu because they learned that many they'd sold in the past year had been modern counterfeits. They seem to be primarily coming out of Japan, often through eBay.
The stamps appear to be fairly consistent and easy to distinguish from genuine Shonai ichibu once you know what to look for.

Graded MS63 in 2021, before the counterfeit stamps had been identified

Graded MS63

Graded XF Details



The lines in the counterfeit 庄 stamp are very thick compared to genuine examples, and the edges are very clear and defined. Genuine pieces have thinner lines and are less evenly struck, with some edges being very vague. Additionally, all the lines in the countefeit 庄 stamp are the same width, while genuine examples have lines that taper and change thickness. The geunine 庄 stamp is also often seen placed more haphazardly on the coin; it's always to the right of the original coin text, but it may be closer to the top or bottom. Counterfeit examples are very consistently struck near 分.



Similarly, the counterfeit Y stamp is very chunky and tends to be very evenly struck. Genuine Y stamps typically have much thinner lines and are often struck unevenly, as seen in the center example.
The Rectangle Coins