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. :)
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:
is sente against the corner. Black must defend with
or the corner will die. After that, the reverse monkey jump
destroys black's territory along the top.
and
threaten to make ko of the corner.
defends, after which
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.
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.
If white fails to realize that the descent is sente, and tries to cut off , the reverse monkey jump
turns the whole corner into a ko.
If Black plays the descent in sente, it induces White to defend her corner, Black lose points here compared to playing directly, which leaves the possibility to play other endgame plays against the corner later.
Here, we see the success of the 1-2-3 principle. 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: