Like A Dragon: Ishin has many different substories or side quests for players to get their teeth into. These substories are split into various different categories for each individual location. From Gio, Rakunai, Mukurogai, and many more.
There is a total of 72 substory quests to find and complete altogether. At first these quests will only be available depending on your current chapter. However, none of them are missable. You can come back to them in Premium Adventure Mode. Once the main story has been completed.
Below is a list of these available substory quests.
Shogi (Video Guide)