Carving, boning or slicing
The length of the blade decides how often you have to restart the cut. With 25 and 25.5 cm you go through a leg in a single stroke, and the face of the meat stays smooth, not ragged. The curve towards the tip helps with separating, because you work with the tip against the bone without driving in the whole blade.
For work close to the bone, where control matters more than length, the 23 cm model is the easiest to handle of the four. All the blades are rigid, between 1.8 and 2.3 mm thick, so they don't flex easily and the cut comes out in one pass.
Cleaver or carving knife
The knife cuts meat, the cleaver goes through bone. They are two different tools with two different purposes. If you use a butcher knife to crack bones, the edge can be damaged in a few blows.
For bone you have bone cleavers, with thick blades made to take the impact. For mincing and chopping on the board, professional cleavers are the right tools.
How often do they need sharpening
Less often than you'd expect. The blade of an ordinary knife has a hardness of 54-58 HRC. DACOBI butcher knives have blades with a hardness of 60 HRC, so the edge isn't easily damaged, unlike the soft steels usually used in butchery. You can cut for a long time without needing a honing rod.
When it finally dulls, a fine whetstone brings back the sharpness and keeps it for months.
