Grev, I think the kanji for the word you are looking for is 阿波 and should be read as ‘Awa’, though google translate may incorrectly render it as ‘Awaho’. Listings for these koshirae and fittings seem to include Matsushiro (松代), Awa (阿波), and Sendai (仙台) in the title. For example: https://aucfree.com/items/l470576566 However, Matsushiro (松代), Awa (阿波), and Sendai (仙台) are all distinct domains, and are spatially fairly distant: Awa is in Shikoku, which is a separate island in the west of Japan, Matsushiro is in central Honshu (the main island), and Sendai is in Northern Japan. So there may be some uncertainty or disagreement over where these fittings originated (Matsushiro, Awa, or Sendai).