Mitsuo Yamatsuka is known for sharpening and finishing knife blades (研ぎ). His registered signature technique is kasumi (カスミ研ぎ), a "hazy" polish, and his stated specialty covers single-bevel, mirror, and double-bevel sharpening (片刃・鏡面・両刃研ぎ).
He was certified a national Traditional Craftsman (伝統工芸士) in the Sakai forged-blade trade in 1999. In 2015 the City of Sakai also named him a certified Meister (堺市ものづくりマイスター) in its knife-making (edge-setting) trade, recognizing his single-bevel (片刃) kasumi sharpening and finishing.