In order to look like the real Murayama who put on weight due to his illness, Matsuyama increased his weight by nearly 20kg and managed to lose the weight towards the end of the filming. Upon seeing that Matsuyama had regained his previous figure, Lily revealed that he actually liked the larger-sized Matsuyama which led the latter to comment that even his wife Koyuki said the same thing. However, if he were to maintain that weight, he could only become a sumo wrestler or play Murayama forever. Lily joked that he can just alternate between those two roles which led Matsuyama to say that he can't do that until his children reach adulthood.
Habu who was Murayama's biggest rival when the latter was live, appeared as a guest during the event and presented Matsuyama and Higashide who played Habu in the movie with the first level shogi license. The two actors expresed their joy at receiving the license and said that it was a honour to be able to show the beautiful ways the shogi players lived to pursue their passion. When asked about his impression of the two actors, Habu commented that he was happy to see Murayama again through the acting of Matsuyama but admitted that he was a bit embarrased about himself appearing in the movie since it's usually people who had already passed away to appear in such films. As such, he was glad to be able to see this movie while he is still alive.
In the movie, there is a line where Murayama said that the only thing that his shogi teacher (Lily) taught him was drinking and playing mahjong. As such, before the filming started, Matsuyama suggested that they should play mahjong once so Lily arranged for Arai Hirofumi and Pierre Taki who were unrelated to the movie to play mahjong together. Lily also joked that during the filming, they teased Matsuyama for giving off the vibe of a virgin despite being a father of three. However, Matsuyama did not mind this nickname at all and even vowed to get the title back from Emoto who was regarded as a level above him in this regard.
Sources: Nikkansports / Sanspo / Sponichi / Eiga.com / Oricon