Konnichiwa Ger-san!
The author, Kiyama Yoshitaka, first worked in the United States, and after returning to Japan he worked in his hometown of
Neu, Hino District, Tottori Prefecture.
Kiyama's birthplace is in the mountains, but it is close to the city of
Sakaiminato, which has been a popular place for the game of Go since ancient times, and this may have been the reason why Kiyama chose to paint pictures of Go.
About
Sakaiminato
About
Hino
As for the model for the painting, I don't think it's a famous shogi player. There are two reasons for this.
1. Sakaiminato is a small town in a much more rural area than Tokyo or Osaka, and it is unlikely that famous Go players would visit it.
2. "下手な考え 眠るに如かず" is a sarcastic expression that expresses the idea that no matter how long you think about it, you will never come up with a good idea. It is a very rude expression to use for famous Go players.
There were many people who enjoyed playing Go in Sakaiminato, which means it would have been easy to find a model, so the model for the painting was likely a resident of Sakaiminato who enjoyed playing Go.
It's just a possibility, and it might not be true.
NANGI