Among the most famous tanto of all is the Aizu Shintogo by Shintogo Kunimitsu, believed to be the master of Masamune. Blade length is approximately 25cm.
This template is based on the historical blade and precision cut from 2.5mm mild steel. Note that the surface is unfinished and may show signs of oxidation and scale, some oiling and care is required occasionally.
Apprentices were asked to make as many kata as they could: these are eventually used for sword making, can be kept for a lifetime for reference and study, and their very making is a good opportunity for practice.
A good to way to learn proper sword sugata, or silhouette, is to make a kata, or pattern, from 1.25-1.5mm thick sheet of mild steel. Learn about making your own kata.