Reverse Monkey Jump

    Keywords: Tesuji
[Diagram]

Reverse monkey jump

Whereas a monkey jump involves jumping with a larger knight's move from the second to the first line, the reverse monkey jump, as the name implies, involves jumping with a large knight's move from the first to the second line, as in this diagram

Table of contents Table of diagrams
Reverse monkey jump
Sente descent
Sente hane-kosumi
1-2-3 principle applied
Inverse monkey jump twice
1-2-3 principle ignored
1-2-3 principle success
Search pattern


Name discussion

Tapir: Has this tesuji a name? Then please add it. Otherwise you can propose one. This page intends to be a page on this tesuji in future.

Bill: Kano Yoshinori in his Yose Dictionary (p. 111) calls the move in the sente descent diagram below a tobi-komi. So do Segoe and Go Seigen in their Tesuji Dictionary, under sagari. Hard to translate. Hmmm. Plunge is not bad. It is often translated as a non-go term as dive. That's not so bad, either. :)

kb: This is really just a version of watari.

tapir: Isn't watari just connecting underneath? Then - of course it just a version of it. But connecting with the normal monkey jump, connecting with a keima watari, connecting with shortage of liberties are all different techniques. At least for me it was quite an "Aaah" as I learned it - and I have seen several opponents in the low sdk-range quite surprised by this - when I played this as an endgame tesuji where they only expected a normal monkey jump.

Feanor?: Warfreak2 proposed the name "jumpy monk" as a humorous inverse of "monkey jump". I personally like it. :)

Phelan: I like it too. :)

Tapir: While humorous it doesn't work at all with languages which use a derivative of monkeyjump (Affensprung in German e.g.). Reverse/inverse monkey jump is translatable. Sorry for my general unfunnyness, but I can't see me explain the german equivalent to beginners.

Situations in which it is used

Sometimes, it is useful to realize that you can play a move as an inverse monkey jump, because you can descend to the first line in sente. Example:

[Diagram]

Sente descent

W1 is sente against the corner. Black must defend with B2 or the corner will die. After that, the reverse monkey jump W3 destroys black's territory along the top.

[Diagram]

Sente hane-kosumi

W1 and W3 threaten to make ko of the corner. B4 defends, after which W5 destroys the base of the black stones, forcing them to run.

tapir: Endgame by Ogawa and Davies has a somewhat similar example threatening a ko to enable a reverse monkey jump. They don't give any name to it.

Applying the 1-2-3 principle

Quite often, it is better to forego the sente move that makes the reverse monkey jump possible, and instead play it directly, consistent with the 1-2-3 principle.

[Diagram]

1-2-3 principle applied

B1 is an application of the 1-2-3 principle. A black move at a is sente against the corner, but black does not need to play it.

[Diagram]

Inverse monkey jump twice

If white fails to realize that the descent is sente, and tries to cut off B1, the reverse monkey jump B7 turns the whole corner into a ko.

[Diagram]

1-2-3 principle ignored

If Black plays the descent in sente, it induces White to defend her corner, Black lose points here compared to playing B3 directly, which leaves the possibility to play other endgame plays against the corner later.

[Diagram]

1-2-3 principle success

Here, we see the success of the 1-2-3 principle. W2 defends against further incursions into white's territory along the top. Black can then switch to the sente endgame in the corner, and can choose to play a when and if that becomes the biggest gote endgame move.


Application in tsume go

Some tsume-go that involve this tesuji:


[Diagram]

Search pattern

unkx80: Did a search using the following pattern. Relevant results:

Related problems:


This is a copy of the living page "Reverse Monkey Jump" at Sensei's Library.
(OC) 2011 the Authors, published under the OpenContent License V1.0.
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