Great game. Great table. Great story.
Yamaguchi prefecture. I had to look it up due to the ambiguous comment.
What are the cards on the table? Stats for the characters?
The story of "why is everyone in this prefecture named Yamaguchi" goes back nearly a thousand years to the 1185 Battle of Dan-no-Ura, at least according to a local historian. The Heike, which were from what is now Yamaguchi Prefecture, lost the sea battle and fled south to Kyushu. They heavily settled in what are now Saga and Nagasaki prefectures, so Yamaguchi is the most common family name in these prefectures. (The story takes place in Nagasaki Prefecture) For example, my in-laws are named Yamaguchi as are the elderly sisters who live across the street from me.
This amuses me, because Yamaguchi isn't even in the top five most common family names in Yamaguchi nor does the name make the top five in any other prefecture.
The cards on the table are the character stat cards for Phantom Ace, Gauge, and Rutherford.
https://www.japantimes.co.jp/life/2009/10/11/general/which-names-are-to-be-found-where/