These knives have a Super Aogami (Blue Paper) steel core with a very high hardness rating that is super easy to resharpen. The core steel is sandwiched between layers of stainless steel. These knives are made from some of the best materials without a high price tag.
As with all Carbon steel knives, these blades will react to any food they come in contact with and should be wiped down and cleaned well before being put away for storage.
The idea behind the shape of the blade is that it encourages a straight up down chopping motion where the full blade length will come in contact with the chopping board and so go straight through the whole vegetable. There is no need to push and pull the knife horizontally through the chopping motion. European cooking tends to use a lot more chopped vegetables than in Japan.