Katana works by swordsmith Yoshindo Yoshihara are seen in Tokyo's Katsushika Ward on Feb. 14, 2022. The one in the back shows beautiful "hamon" wave patterns along the edges of the blade.

Forty years -- 40 years for one sword, 40 years to master one single technique. Half a lifetime for one katana. That's the time Shimpei Kawachi's father took to learn the method of "utsuri," which ...