Oonsoo is a solitaire game played with the beautiful Japanese 'hanafuda' deck of cards. The object is to stack the 4 cards of each of the 12 suits in order of rank, working with only 12 cells into which the cards are dealt. Usually this is impossible, but then the game lasts only a few seconds. When possible, the game is difficult and lasts a few minutes.
The rules are simple, and moving the cards around the cells is just a matter of touching the card to be moved. To make the game easier for beginners each suit has a different-colored border, and within this border the rank of each card is indicated by a tiny 'bar-code'. However there is pleasure in getting to know these cards, apart from the satisfaction of stacking the whole deck in the desired order (when it is actually possible).
Because the games are so short and yet challenging, it is ideal for keeping the mind alert when waiting for something to happen. But beware - it can also become addictive!