hajoucha: WT2, BS7, WT4, BQ1, WS1, BP2 - black lives, white has sente. Why this is not a solution and is marked incorrect?
Farkas: Something isn't correct in your sequence: after T2 (your first move), the answer is always T1, and not T7. please check again (or even better, send an sgf file).
weiqidevil: This problem is flawed. The throw-in at S1 wastes a ko threat.
Farkas: This problem is pretty artificial. The meaning of the throw-in is that T4 became a sente move. Still, its value is questionable. I also added sequences.
Something is wrong with the sgf. At some point the defender plays on places where there are already stones...