Mini-Games
As with previous titles in the franchise, Yakuza 6: The Song of Life is loaded with Mini-Games to distract Kiryu from his main quest! Kiryu is rewarded with experience points whenever he plays, and he can get some really cool rewards such as special equiappable items if he excels.
Time essentially stops when Kiryu is playing a mini-game, so there is never a reason to rush. Sometimes the game will ban Kiryu from playing if there are plot reasons, and these are noted in the Walkthrough. Usually however, you can play mini-games any time for rewards or just distraction!
Take special note of the Clan Creator. Of all the mini-games, it will net you the most cash in the fastest time. If you ever need to grind for yen, that should be your destination!