Japanese popular dictionary "Koujien" explains Tosenkyo as follows.
One of the games since Edo-era.
After perching the target like a leaf of ginkgo-nuts called "Chou" (means butterfly) on the wooden box called "Makura" (means pillow), the player sits on the knee at a distance of about 1 meter, and tosses an opened fan (called "Ougi") to the target.
Then the judge (called "Gyouji") determines the name and score for the situation among the fan, the target, and the box, simulated Murasaki-Shikibu's "the Tale of GENJI".
It is related that this game started in 1773.
That name is just like as hand in poker game, for example 0 point "Tenarai", 1 point "Hanachirusato", 50 points "Yumeno-ukihashi", and so on.
But, can you get clear image from the above explanation? Perhaps you don't have any experience to play Tosenkyo, so I'll try to explain visually in this corner.
This site introduces Tosenkyo with movies.
This DVD introduces "GEISYA-ASOBI" including Tosenkyo.
In this movie, all members wear KIMONO, and English caption comments each play.
If you have any questions about Tosenkyo, please feel free to visit bulletin board.