Yang Yilun's method of approaching life and death

    Keywords: Life & Death, Theory

The following method is the method lectured on and endorsed by Yi Lun Yang 7d who teaches in the U.S. and on line.

If the problem is to live and not just a capturing race, then a systematic way to solve life and death problems is to ask the following questions:

  1. Is there an eye point inside?
  2. Is there a point that divides the area into two rooms?
  3. Can you expand your eye space to get more room?

At each step of the process start at 1) and work your way down until the problem is solved.

An example:

[Diagram]
Black to live (1121 from Go Problems)  
[Diagram]
An eye point  

B3 is also a vital point, but White plays W4 and it's ko. So let's change the last move that got us to ko. There is no point inside that divides the area to live in, into two 'rooms', so we skip step 2 and move on to step 3. Expand the eye space.

[Diagram]
 

But there's not enough room to live. So we've exhausted the steps, and need to fix the first move. There is no other eye point, so we choose a spot that divides the inside area into two rooms.
We have exhausted the possibilities that come from this B1. All end in death. Therefore we must reject this B1 and look for other moves for B1.

[Diagram]
Divide into two rooms  

B1 creates two small rooms within Black's group. As a result of B1 both W4 and B5 are eye points, so Black will play one of them (miai), and live.

[Diagram]
 

White can try some squeeze plays as well, but rather quickly we found the important points to solve this problem. The hardest point in a life and death problem is when you need to expand your eye space. A few tricks are necessary for that.



If the puzzle is to kill then use these steps instead:

  1. Is there a vital point inside?
  2. Is there a point that divides the area into two eye spaces?
  3. Can you squeeze the eye space to give him less room?

The hard part about killing is seeing how to squeeze best. Sometimes it involves a very clever sacrifice.

The method listed above is the method lectured on and endorsed by Yi Lun Yang 7d who teaches in the U.S. and on line. In fact, it uses his precise terminology - particularly the term "eye point" which was invented in collaboration with his students.

This method has some real advantages. First, it organizes your reading and helps find correct solutions. Second, it discourages throw-ins until they are absolutely necessary - avoiding lost points when we humans misread.



Yang Yilun's method of approaching life and death last edited by Dieter on December 10, 2012 - 11:11
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