Kindly appreciate if anyone can comment on why Pros play such moves. I've seen them commonly played a lot by pros and can't understand why. Based on my SDK understanding of Go.

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This is played by Takemiya(B) vs Imamura Toshiya (W). Why does Takemiya not block at Q2? It seems better.

I dont see any advantage from doing the jump to P2. It seems it would work well only if White just pushes at Q1 straight.
If White jumps to P1 then it seems even worse by getting reduced more than just blocking at Q2 (and the standard hane, block, connect sequence).

I also don't even see any sente advantages.
If White jumps to P1 then whether black O2 or O1, Black still ends in Gote anyway (when White pushes again at O1/pulls back at Q1).

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In this game played by Zhou Hexi and Piao Wen Yao. Why does he push at S11 and not do a monkey jump to T12/T13. Doesnt that reduce more points? Or is this simply to reduce and end in sente? Even if it reduces less.

For your second question I can see the reason. If Black takes the more profitable jump, then after White gets a stone at S11 and pushes in at R10 there is some aji at P11+Q9 if Black protects S9.

For the first question there must be similar aji but it's harder to find. I believe White might get M8 in absolute sente if Black responds with bad shape.

I'm just a lowly kyu, but in both cases your suggested moves are screaming bad shape/weakness area all over. I may play them in a game of mine, but pondering over them I wouldn't.

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Geek of all trades, master of none: the motto for my blog mostlymaths.net

In the first one black doesn't need to defend the o2 cut if white does p1. So jump is not 2 points worse than q2. However if the k2 stones were further away then q2 would indeed be better. If white gets q1 for p1 in sente then it's the same as if black did q2, but if black can get q1 in sente it's a little better for him.

In the first position, let's take as baseline your suggested sequence: R1-Q2-Q1-P1-S1-P2. This is all sente for W. Now compare to the game sequence: R1-P2. If B later gets Q1, he does two points better than the baseline. If W exchanges Q1-P1 first in sente to prevent this, it is nearly certain that B will later get Q2 in sente (as it is only 1-point gote for W), for the same result as the baseline. Finally, if W continues P1-O1-Q1-(S1-T1)-Q2-S1, B does not need to connect at O2, so W does only one point better than the baseline in gote, which is unlikely to be a good idea. The conclusion is that there is no territorial advantage either way. However, there is one additional consideration -- the entire W group is not completely alive! So B does not want to force W to connect at S1. The game sequence accomplishes that objective, while the baseline sequence does not.

Thanks for the responses! Yes I forgot for the first diagram that after blocking, the cut need not be protected due to K2 wall. And that the jump doesn't induce W into connecting S1 for his group to live.

Could there be more help regarding Diagram 2? Regarding why it is so common to push (like S11) and inducing the opponent to block (at S12)than monkey jumping.

What about these moves is haengma?

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Patience, grasshopper.

I won't claim to have a full understanding about what haengma is, but it's an interesting topic.

Sometimes, I've heard "haengma" described as the technique of moving stones. For example, it's not uncommon in a discussion on haengma that different connection relationships (eg. large knight's move, one space jump, etc.). This makes sense, I guess, given the Chinese characters behind the word (行馬).

Since you asked about haengma here, I looked it up online. I found a very brief entry from Wikipedia.

Basically it says, "In the game of go, haengma is the process of placing new stones and extending your influence in an area where stones already existed."

I suppose this is consistent with ways of "moving" stones (one space jump, etc.), since you start from a place where you already have stones, place a new stone, and extend your influence in that area.

One other idea that I can add is that, from my go book collection, it's quite common for me to see books that group together problems related to haengma and "maek". Maek, which literally means "pulse", seems somewhat similar to the English usage of "tesuji" from where I've seen it. So perhaps it can be said that haengma, too, can be related.

One final example is the usage that I've seen from Inseong from the Yunguseng Dojang. In this kind of shape:

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

I believe that he indicated that the "correct haengma" was this:

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . W . . . . |
$$ | . . . , . . . . . , . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Here, the white move is not extending the influence of stones that have already been placed. To me, it seems to rather be limiting the influence of the black stones that have already been placed. So perhaps the Wikipedia entry isn't the only usage of the term.

Aside from usage examples, the best I can say is that one possible explanation of haengma, for some cases, is related to placing new stones on the board to extend your influence. But as it may not be the only usage of haengma, and may not always apply, I'm not sure if that's a very helpful definition

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be immersed

Because the monkey jump is gote but the push is sente, and it's not often worth taking gote to take away those few extra points. It's not a local question: if that's the only valuable move left on the board then obviously taking gote is better, so it depends what other moves are available as to which is best.