Santoku is a derivative of a Gyutou, it is a multi-purpose knife that is meant for home user."Santoku" literally refers "three virtues" in kitchen, which includes meat, fish and vegetable. It has a straight blade that is more convenient for chopping vegetables.
The size of Santoku is slightly smaller than Gyutou, its common blade length is around 17-18cm. Nowadays, it has become the most popular knife in home kitchen!