Handguard are one of the materials that you will need together with Sakura Bloom to ascend Ayaka. Not to mention, you will also need a ton of handguard to upgrade Ayaka’s talent ascension. And to help you, this is the routes you can use to farm handguard by defeating nobushi in Inazuma.
If you need a video demonstration, I truly hope this video below will help you find all the nobushi. I’ve also included a tracker and the minimap so that you can navigate and follow the video easier.