First, to answer your implied question: no, this knife isn't Japanese. Recurved blades of this shape are most common in India (often seen on chillanum, khanjarli, and bichwa daggers (each of which is characterised by a distinctive style of hilt), and also with other hilts). The ornamentation at the base of the blade is also similar to that seen on many Indian daggers (and some other weapons). This is an ornamental brass replica, rather than a real weapon, so it's hard to tell for sure. There is nothing Japanese about this particular dagger/knife.

Second, to answer your asked question, yes, the Japanese did use curved knives. While Japanese swords are famous for being curved (and the naginata even more so), Japanese tanto tend to be much straighter. Despite that trend, there are some quite curved tanto out there, and there are some with concave curved blades - the kubikiri (see https://www.japaneseswordindex.com/unji.htm for an example and discussion) which appears to be a tool rather than a weapon. Japanese tools include many curved blades (billhooks and sickles with concave curvature, and a variety of blades with convex curves). Japanese kitchen and butchery knives tend to be fairly straight (but often have curved edges); one of the more curved ones is the kujira hocho, used for butchery of whales and large fish: http://zknives.com/knives/kitchen/misc/type/Kujira_Hocho.shtml Recurved blades - partly concave, partly convex - are very rare in Japanese traditional knives; today, one can find occasional Japanese bush/camp knives with recurved blades (but usually with much less curvature than this brass knife), but despite the traditional handles and forging, these styles appear to be modern.