TherapieGo: After S17, T18, T17, T16, T19, Q18 we can also play T15.
Also, when we can choice P18 or P19 and the opponent play S18 we can also play take in T18 or T15.
Solomon: At the end of the right sequence many mooves that reduce white liberty kills. It's very annoying to get false answer. I know about the argument of always take external lib but still..
After S17, T18, T17, T16, T19, Q18 we can also play T15. Also, when we can choice P18 or P19 and the opponent play S18 we can also play take in T18 or T15.