The so called japan's new smart tank is still under development, it is not comparable. Anyway, Japan did build good tanks, the type 90 tank is a good tank with the exception of its engine. It's two stroke diesel engine makes it operation range very short. Besides its' tank gun is from Geman Rhein Steel. It is not 100% Japanese tank, when the most important part has to be imported from foreign country.
In case of the Korean tank, possiblly it is a good tank. But when we consider the fact that it's fire control system and tank gun are imported, possiblly the engine also, you can not put it in the list of best tanks.
While in case of the chinese type 99, this tanke is 100% chinese. Some technologies (e.g engine, tank gun) die come from foreign countries, but we have studied the technologies and is able to make further development based the acquired technology.