RTGProblem102/Attempts

Black can kill  

Dieter: I know the solution now, but I want to discuss here why I find this problem difficult.

1. It has a starting width of 6 (for me): 6 moves I can't dismiss without reading. a and b narrow the eyespace, while all of c, d, e and f look like vital points
2. The 3rd move is a blind spot

Reduce  

If we play the two reducing moves, then White lives. This shows two vital points.

Reduce  

here doesn't work either but already hints at the solution

Reduce 2  

If we try , we fail again

Vital point 1  

This is ko and looks like the best Black can do.

Vital point 1  

Ko again

Vital point 1  

Dead

Vital point 1  

Bad ko

Vital point 2  

Fail

Vital point 2  

Fail again

Vital point 2  

Fail

So, I couldn't solve this problem and would definitely misjudge the status here as 'Black can make a ko'.

But black can kill. We have found but is the blind spot.