The rarity of Riki's Sange and Yasha is Uncommon. At this moment the item is available for trade.
Riki's Sange and Yasha is a skin for Riki. The skin was added to the game on Invalid Date, it was created by Vladimir >the implyer.
Riki's Sange and Yasha is currently one of the most popular skins, but it is rarely seen in the game due to its high price.