This article introduces Japanese culture from Jujutsu kaisen vol.4.
In this volume, you should know funny social problem in Japan (prank by a part-time worker) to understand background of the characters action and words.
Playing catch with old rice ball
In chapter 32, there is a scene that Gojo and Nanami discuss how to tell Itadori alive to Fushiguro and Nobara.
In the scene, Gojo said “Playing catch with old rice ball” to Nanami.
I think this doesn’t make sense to people who don’t know recent Japanese social problem called “terrorism by part time job worker.” (please refer Wikipedia for your understanding.)
part-time employees perform pranks and stunts, such as climbing into ice cream freezers, or holding their body horizontally suspended, more colloquially termed ‘planking‘, on the counter-tops at fast-food restaurants, usually with the sole purpose of gaining recognition from their peers through the photos and/or videos they later display on social media sites.
Wikipedia https://en.wikipedia.org/wiki/Part-time_job_terrorism
In around mid of 2010’s, this kind of disgraceful performance get attention from people which caused viral in SNS. It looks Gojo try to do the same for killing time. (he looks depressed by the incident Itadori faced a little bit)
On top of that Gojo said “separation of church and state” to make it more controversial. lol
(by the way, in Japan it is said “separation of region and politics” since church is not common in Japan)
Yamanote line game
Quote 呪術廻戦 Volume 4 Jujutsu Kaisen chapter 32
The next scene from the above suddenly Gojo start clapping and asking “what points do you like about Gojo”. Readers who don’t know the Japanese game may wonder why Gojo behave like this. This game is called “Yamanote line game” which named from real one of busiest train line in Tokyo. (each person join the game keep speak out the answer in decided theme in tern) Anyhow Gojo try to change the bad mood they are having.
Please refer the video if you want to know the game exactly.