White to play and win  

W1 and B2 are miai, but White chooses W1 to get the reverse sente at W3. Then Black takes his sente with B4 - W5.

Failure 1: Wrong miai

Failure 2: Wrong reverse sente

Failure 3: Premature reverse sente

Stout resistance  

Next, B1 - B5 force White to keep pace with W2 - W6. Otherwise Black can make jigo. But W6 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

Failure 1

Wrong miai  

If W1 takes the wrong miai, Black takes his sente with B2 - W3 and then takes the other miai with B4. After B10 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 W3 instead of W6, but W3 is a mistake.

Wrong reverse sente (ii)  

After W6 we have not reached a miai. Black continues with B7. Now B9 - W10 is sente because of black+circle and white+circle. After W10 the last two plays are miai. The result is jigo.

B7 is worth 1.5 points, not 1, so B5 is sente. But after White replies at W7, B6 is tedomari, and Black gets jigo.


Failure 3

Premature reverse sente  

If White starts with the reverse sente at W1, Black takes the right miai (for him) with B4. After W5 the position has transposed to the Wrong reverse sente diagram.

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

PracticalEndgameTest6/Solution last edited by on August 4, 2004 - 20:19
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