Kirk here. I am one of a large number of people in Kumamoto to have had the pleasure and honor of visiting Matsunaga-sensei's smithy (kajiya; the place where he actually makes Japanese swords). When I visited, he allowed us to experience tameshigiri, using a real sword to cut through pieces of rolled up goza (the top layer of a tatami mat). I think many readers of this page know Matsunaga-sensei much better than I do. I'm only writing about him today because he came up in a conversation with my wife and that conversation led me to the following article:

https://www.visit-kyushu.com/en/discover/blogs/world-katana-sword-making-kumamoto/

If you're interested in Matsunaga-sensei, you may be interested in learning about Colin Young, a man who studied with Matsunaga-sensei and then started his own dojo in the UK:

https://www.thenorthernecho.co.uk/news/1221404.swordsman-point-make-traditional-values/

P.S. Until today I thought "smithy" as a nickname for someone named "Smith." Today I learned for the first time that it's a real word and refers to the workspace of a blacksmith.