I bought 2 of these knives to my 9 and 11 year old a little tired of the struggle at the restaurant with poorly sharpened knives. They use only table, playing ban with of course because the blade is sharp even at its rounded end. Only downside the opening and not always easy even after greasing lock system. Having had several opinel slip rings some much better than others I find that this system deserves better attention to the particular assembly that a child can quickly become discouraged and even hurt power to insist on a ring hard to turn.
