An Unexpected Effect of The Suicide Rule

About a year and a half ago, I published my first article on my now inactive Go Magic "psygo's Corner" column. In it, I argued that the suicide rule was unnecessary, and that the game would be strictly richer if we dropped it.

psygo's Corner's first article.

My opinion remains the same. Let's now take a look at how it was actually even reinforced.

A few months after that article went public, Park Jeongsu 박정수 4p, one of BIBA's — Blackie's International Baduk Academy, a Go school for foreigners in Korea; have a watch of this video for more info — substitute teachers, wanted to show us how the Ing Cup's unique set of rules changes the game. That day, he mainly discussed this situation:

Dia. 1.

Who wins the capturing race inside? Is it a seki?

That capturing race is an example of the "big eye kills small eye" principle:

Dia. 2.

Black 2 and 4 are played elsewhere.

Dia. 3.

Since Black cannot play at A, the triangle points are a privilege of the group with the bigger eye.

However, something very unexpected happens when we take away the Suicide Rule, which is one of the Ing Cup's quirks — the Ing Cup is considered to be the Olympics of Go, by the way, its most important tournament, happening only every four years. What then is the outcome if Black is able to play at A in diagram 3?

Dia. 4.

Black can now race with White more freely.

After the inner liberties are freed, Black is able to turn the intersections between both groups into normal liberties, preventing them from being privileges. So the final result is a seki now. Note that we have to be careful about how many inner liberties White has and how many common liberties both groups have, as this turns into a more normal capturing race, without any special advantages for White.

In the end, we have that the asbence of a suicide rule grants the "big eye vs small eye" liberty race type more possibilities. Instead of it being a straight win for the bigger eye'd group, now we have to examine if a suicide could erase the privileges.