These are what people tend to generically call "sushi knives". They are the main knives used in traditional Japanese food preparation, with a heavy emphasis on vegetables and fish. In my opinion they are very specialized tools, and not really suitable for everyday home use. With that said, if you REALLY have your heart set on one, they are super cool and interesting and most definitely individually hand-made, but honestly, just don't expect to use one as your "daily driver" for cutting your onions and chicken for dinner every night. Note that most are single-bevel, and so ONLY for right-hand use, and most are carbon steel and so very hard (and potentially more fragile and prone to cracking or chipping) and more prone to rusting, discolouration and pitting. It's sort of like owning a high-end sports car, it can be fun and interesting, but you need to be ready for serious maintenance and skilled use.