Shintōgo Kunimitsu

Source: Wikipedia, the free encyclopedia.

Shintōgo Kunimitsu (新藤五国光) was a Japanese swordsmith and was especially famous for making

Shōwa and Enkyō
periods, generally acknowledged to be the teacher of master swordsmiths Masamune, Yukiimitsu and Norishige. This is due to various similarities in style and workmanship that indicate that Masamune was almost certainly his student.

An example of his work is known as 'Aizu Shintogo'. It is a tanto of 25.4 centimeters in length.

He had several sons, who likely crafted a number of swords under his name.

References

Book: Japanese Swords by Nobuo Ogasawara (tenth edition, printed 1986)