Talk:Drop List/@comment-70.162.219.37-20150711214616/@comment-26215551-20150712000537

The rarities are stated in-game - it's the number of static sakura petals under each sword's name in Team Formations. This is based off of both sword type and their status in real life. For instance, most Tachis are Rarity-3 (have 3 petals), but those that are imperial treasures in real life are Rarity-4 (e.g. Tsurumaru and Uguisumaru).