PracticalEndgameTest6/Solution

White to play and win  

and are miai, but White chooses to get the reverse sente at . Then Black takes his sente with - .

Failure 1: Wrong miai

Failure 2: Wrong reverse sente

Failure 3: Premature reverse sente

Stout resistance  

Next, - force White to keep pace with - . Otherwise Black can make jigo. But gets tedomari to win by one point.

Final miai  

Finally, the last four plays are all miai. The order of plays does not matter. White wins by 1.

WillerZ found the solution.

I concocted this for Dave, who wondered about "assessing reverse sente dynamically". I also wanted to show the difference between the initial miai, which made no difference in the previous problem.

-- Bill Spight

Wrong miai  

If takes the wrong miai, Black takes his sente with - and then takes the other miai with . After the remaining four plays are miai. As with the Final miai diagram, the exact order of play does not matter. The result is jigo.

Failure 2

Wrong reverse sente  

At first it appears that White can play the reverse sente at instead of , but is a mistake.

Wrong reverse sente (ii)  

After we have not reached a miai. Black continues with . Now - is sente because of and . After the last two plays are miai. The result is jigo.

is worth 1.5 points, not 1, so is sente. But after White replies at , is tedomari, and Black gets jigo.

Return

Failure 3

Premature reverse sente  

If White starts with the reverse sente at , Black takes the right miai (for him) with . After the position has transposed to the Wrong reverse sente diagram.

Note that each player prefers a different play in the initial miai.