HolIgor: This is not a real test of yose skills. On the 10x10 yose board black needs 51 points to win. Black has 52, so the only problem is a ko in the upper left corner. Black has to eliminate the only ko threat.
It is a simple yose problem, in that all you have to do is find the largest play and make it. I do not think you would call this a tesuji or life and death problem. ;-)
unkx80: Which is why I stuck it with an Intermediate difficulty level. =)
Thad: The answer should be obvious. Form the all powerful double B2 Bomber with 1. White starts the ko. Black takes right back. White has no ko threats, so starts to make the other ko. Black takes all upper right stones off the board.