Do you recommend to read some book on semeai like "The Theory and Practice of Semeai" or Robert Jasieks book "Capturing Races"? I really suck at capturing races, will that ability improve enough just by doing tsumego? What do you think Lee Sedol, for example, knows about it? I don't think he studied complicated formulas, did he? I'm not bad at tsumego, but I always play capturing races out. What do you recommend? Is reading such a book worth it?

Like many topics of go theory, there are several approaches to the semeai topic and a combination of several approaches has good chances to succeed in making you stronger at semeais. Possible approaches:

- semeai theory (about counting liberty differences correctly, move order etc.)
- reading
- accelerating (in some cases: replacing) reading by means of semeai theory
- learning related topics, such as life+death or functions of shapes

Complicated formulas? No. Currently, one(!) very simple(!) formula suffices for all the basic cases. Nevertheless, one must know for whom the inside liberties count and how to think about approach defects etc. Not the formula is complicated but the side conditions that can make semeais non-basic.

Some book? No. Every book teaches something different. Choosing books well is important, or read them all. And yes, every semeai book has quite a lot to say to somebody knowing very little about semeai theory. (The same cannot be said for many topics of go theory. So if you like go books at all, hesitating with semeai books would be strange, unless you have still more urgent weaknesses to improve.)

EDIT: always playing out semeais can be a loss of many handicap stones. It is essential to know by how many moves you win or lose a semeai.

Yes, studying semeai is well worth it. Potential semeai is almost universal towards the end of the game, as dame get filled in.

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