Question about Kai Shun combination sharpening stone 300/1000 grain

Well, since it is a rather generic whetstone of the lowest price range, I wouldn't worry too much about the manufacturer. Kai is 99% certain not to make these stones themselves. Judging by the price, this will be a similar or exactly the same stone as so many generic, cheap combination stones. But when it comes to cutting, 99% of the time it is the technique that determines the result, not the stone. If you are looking for really high quality stones, then I recommend you take a look at the Naniwa Chosera (or Naniwa Professional as they are called outside Japan) or if you want to get really fancy, then something like Shapton Glass etc.. But then, depending on the grit, 1 stone (not a combination) can quickly cost over CHF 100. This combi whetstone is a "budget" stone. Are they bad? No. With good technique, the results of cheap and expensive whetstones are comparable. The feel, speed and durability of the stones drive the prices up. You are probably better off with a noname grindstone because you don't have to pay for the logo that Kai slaps on it. This stone is definitely in the cheapest segment. How cheap? The guy who says it's cheap must be crazy! No, even ~100 CHF for a single Naniwa Chosera is not too much when you consider that such a stone for normal household use will probably last for decades.

The stone is in its original packaging. Mine didn't have a stamp on it either, but otherwise it looks exactly like the picture. What matters to me is not the stamp, but the sanding result - and that is top!!!

This is a good whetstone. It was a winner in a product test a few years ago. Mine has a logo from Kai.

Thank you for your reply, however, I do not want to spend money on something that is not the original...for me 79sf is a lot of money for a grindstone, I wanted a Kai Shun grindstone, except that the packaging seems to be original, does not mean that the stone is, because it should have the original Kai Shun logo on it and also the grid size....