Recently, the phrase "When in doubt, tenuki!" has been referred to so many times here on SL, that it probably has acquired the status of a Go proverb. Why this is reasonable advice has been summarized by Bill Spight in comments to the teaching game 53:
I fully agree with this advice! I'd say in a typical nine-stone handicap game, I may well catch up around 20 points in the endgame just because my opponent answers my moves too submissively. Instead he/she should sometimes take sente to play elsewhere. And I certainly include myself in the list of people that may get overly involved in a local fight.
But then, I also disagree, and that's why I created this page. (Probably I disagree not so much with the advice itself, but with the way it sometimes gets applied... I would believe -- maybe I should say, I hope -- that our most-respected sensei around here would actually agree with the revisions of his advice. I would be glad about comments!)
If your opponent has just invaded your territory -- please, please, attack him! (Not to kill, but to benefit from the attack, of course.) If your opponent just played an attachment -- please, please, react! In any situation where an additional move makes a huge difference shapewise for both side -- please, take the good shape! If you have a weakish group, and your opponent has one nearby, too -- go and turn the balance of power to your favor immediately!
So how do you know when to tenuki? I'd suggest to rephrase the statement a little:
If you are in doubt, and if it is just about points -- then rush to tenuki!
So if it's about getting superior shape, or about two running groups, chances are you shouldn't tenuki.
Probably I should add examples here, but instead I will begin by discussing this on various game pages where this issue has shown up. See the links listed on the left below "Referenced by" for such discussions.
--dnerra
Bill: Nice page, Dnerra! :-)
I think we are largely in agreement. :-)
On Tenuki is always an option I give some concrete indicators of when to consider playing tenuki.
Tamsin: As an interesting exercise, play through the first 50 or 60 moves of some games from www.gobase.org and count the number of times tenuki is played. Note also under what conditions tenuki is not played.
I have taken the liberty of summarising the above information in the following table:
All the same caveats apply: there will be times when you can tenuki in situations listed under "Don't Tenuki" and times when you cannot tenuki situations found under "Tenuki".
Dieter: I did the exercise. I added the issues about being sealed in.