We are seeing at various trade shows around the US, companies offering copies of Iwako and Zensinsyoji Japanese erasers. Some have names such as Tomiko and Crazerasers. They do not exhibit the superb design and finish that Iwako and Zensinsyoji are known for. Of course they wholesale for a lot less than the Japanese erasers.
When Pokemon cards were the craze, we offered both the US and Japanese versions, but they were both is short supply and we had them intermittently. It was much easier to find the copies in stores and on the street and kids, at least initially, bought the copies in absence of the real Pokemon cards. We saw that kids who had bought the fakes, soon were looking for the real Japanese version or real US versions of the Pokemon cards. Disdain and mockery in the school yard is a powerful motivator.
We have seen the same thing happen in the store, where parents will ask us if the erasers are "The Japanese Erasers" as those parents had bought copies only to have disappointed children.
The 2 sets above are examples of copies we bought at retail. We like the odd yellow and blue colors of the Coke and Pepsi drinks. The licensing fee from Coke and Pepsico would be prohibitively expensive and you would most likely never see their labels on authentic Japanese erasers. On the second set, we like the copy vegetable erasers on a card intended for perhaps a police eraser set. "War against crime and violence" the copy claims.