The idea of a single cut doesn’t surprise most chefs but try to cut fish with a knife that isn’t appropriate and you’ll fail. The knife in most countries is multi-purpose but in Japan a single blade does a single job.
As with every art form in Japan, there are hundreds of years of accumulated knowledge and experience passed down from master to apprentice. Specific rules and procedures of the trade passed on have helped develop their products.
In Japan, there is one region that is world-renowned for their metal work is sakai city. Sakai has been known for their metal work since 500 A.D. and some of the best blacksmiths are still there.