SAMURAI WARRIORS: Spirit of Sanada

The base accessories are automatically obtained when you finish battles. In order to get all of the accessories, you will need to play the Exploration Stages: Each exploration stage has its own accessory that is unlocked by either completing all of the exploration goals for that stage or by defeating a Secret Treasure Unit and picking up their drop.

For each exploration stage, your goal will be complete the Exploration Goals for that stage but if you see a Secret Treasure Unit (a random chance of spawning in a random area, will show on map as a big red dot if they are in the area you are currently in), stop what you're doing and make sure to defeat it and pick up its drop ASAP, because this will grant you the accessory immediately. If you are lucky enough to find the Secret Treasure Unit before completing all of the goals, you're done: move on to the next Exploration Stage. If you complete 4 of the goals for a stage without encountering the Secret Treasure Unit, a 5th goal will appear that requires you to defeat an officer (you do not need to leave the stage and come back) that will drop the same accessory.