From what I read, it seems to be a fascinating place! From Wikipedia:
Sakai (Japanese: 堺市, Hepburn: Sakai-shi) is a city located in Osaka Prefecture, Japan. It has been one of the largest and most important seaports of Japan since the medieval era. Sakai is known for its kofun, keyhole-shaped burial mounds dating from the fifth century. The kofun in Sakai include the largest grave in the world by area, Daisen Kofun. Once known for swords, Sakai is now famous for the quality of its cutlery. As of 1 January 2022, the city had an estimated population of 819,965,[2] making it the fourteenth most populous city in Japan (excluding Tokyo).
So, Sakai is famous for its metal forging, and also it's one of the birthplaces of the traditional Japanese tea ceremony. Thus, both of Kazuki's Sakai sponsors are related to these industries: iron ore business Senshu Koki, and HD Flower Holdings (flower arrangements are a must for traditional tea ceremonies). Isn't it cool?
Thank you for sharing, this was one of my favourite Sauna Bro's articles so far! I thought it was cute when he said he was jealous of the couple together at the sauna, and he hopes one day when he marries he will be able to enjoy the sauna with his spouse. I think he is really a romantic at heart

I can't help but hope he will find this special person who deserves him, I remember a few years ago he said on a IG live that he would love to have a girlfriend, but girls tend to think of him as friend material rather than boyfriend material lol