Kato became a professional in 1990, and in the same year was promoted to 2 dan. In 1996, he had already reached 6 dan, and became 9 dan in 2011.
Kato began his career as an expert in 1990, and simultaneously received a promotion to 2 dan. By 1996, he had reached the rank of 6 dan, and was promoted again to 9 dan in 2011.