The Totsuga No Tsurugi (十拳剣), literally "Ten-hands Long Sword", is a sword in Japanese mythology. It was once in Asama Miya's possession as mentioned by her and can be seen in a flashback. Miya mentioned, when she left MBI she threw it away.
This Wikipedia Article explains the myth in more detail.
- ↑ Sekirei Manga chapter 73