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View Full Version : Bahr's rule- worth learning?



Paul Cavezza
13-04-2010, 01:47 AM
I've come accross a few really badly worded explanations of this rule, is it worth learning or easier to just count the moves?

Thanks!
Paul

Capablanca-Fan
13-04-2010, 10:32 AM
Bähr's rule is quite useful, since it is a clear case where passed pawns should NOT be pushed. Here is an explanation (http://likesforests.blogspot.com/2007/08/rook-pawns-outside-pawn-ii.html).

The point is, to draw against a lone rook's P, the defending K must reach bishop-1. So it's an advantage if the diversionary P must be captured far back; this means the K's path must be backwards, and can be "shouldered" by the attacking K on knight-7 or knight-8. A more advanced diversionary P allows the defender to reach his first rank and slide into bishop-1 unshouldered.

As for whether to learn it, it's a bit like the rule of the square: sure, you could play it out, but the real point is to evaluate such a position at the end of an analysis. It doesn't apply when the attacker's blocked rook's P is on the fifth rank (http://soapstonesstudio.blogspot.com/2008/01/endgame-caveat-3-bahrs-rule.html).

Paul Cavezza
16-04-2010, 08:53 PM
Thanks Jono,
I found the same link earlier and posted it on my blog:>

I don't know why this rule is so clumsily worded in chess literature. After reading Lamprecht & Mueller's Ch. 5 of secrets of pawn endings I was pretty confused about whether I should count from the defending pawn, my blocked pawn, or my passed pawn.

Capablanca-Fan
07-07-2010, 07:52 AM
Thanks Jono,
I found the same link earlier and posted it on my blog:>

I don't know why this rule is so clumsily worded in chess literature. After reading Lamprecht & Mueller's Ch. 5 of secrets of pawn endings I was pretty confused about whether I should count from the defending pawn, my blocked pawn, or my passed pawn.
See the game Cheng–Steadman (http://chesschat.org/showthread.php?p=282588#post282588), where 56... Ke3! rather than Kg3? wins the outside passed P such that the remaining blocked rook's pawns enable a win according to Bähr's rule.

FM_Bill
25-10-2010, 06:32 PM
The rule 'a passed pawn must be pushed', is too simple.

I prefer 'a passed pawn gets stronger as it advances'.

There are many positions where its best to delay advance of a passed pawn.

Also the rule 'whether trying to win or draw, advance a blocked rook pawn (when there are no knight pawns) as far as possible' fits in with Bahr's rule.

Igor_Goldenberg
26-10-2010, 08:47 AM
Also the rule 'whether trying to win or draw, advance a blocked rook pawn (when there are no knight pawns) as far as possible' fits in with Bahr's rule.

Spot on about rook pawn! Unless I can calculate pawn endgame to the very end (which I often can't!) I'd follow this rule 100%.

Garrett
26-10-2010, 08:50 AM
Spot on about rook pawn! Unless I can calculate pawn endgame to the very end (which I often can't!) I'd follow this rule 100%.

I wouldn't just piss away reserve tempi like that without careful consideration, especially if the pawn stood on the second rank and had the option to move one or two squares.

Igor_Goldenberg
26-10-2010, 08:55 AM
I wouldn't just piss away reserve tempi like that without careful consideration, especially if the pawn stood on the second rank and had the option to move one or two squares.
As Bill noted "blocked rook pawn (when there are no knight pawns)". In this case you are not likely to gain a tempo as you don't have a "free" pawn move. If you don't move your pawn, your opponent will.
You can, of course, construct few examples that serve as exception, but it's one of the most important "rule of thumb" for pawn endgame.

Capablanca-Fan
04-10-2017, 11:20 AM
Here is another page on Bähr's rule (http://fraserheightschess.com/Documents/Bahrs_Rule.pdf) with some exercises as well. In the QLD Champs 2017 thread (http://www.chesschat.org/showthread.php?16999-2017-Qld-Champs&p=430697&viewfull=1#post430697), Solo discusses a modified form where the defending K starts two ranks in front of the outside passed P, so the defending P must be a rank higher to draw.

Patrick Byrom
04-10-2017, 03:00 PM
But is Bähr's rule worth learning? Probably, but there are a lot of far more important endgame rules.

Max Illingworth
04-10-2017, 04:28 PM
Bahr's rule is pretty easy to learn and remember if you read Dvoretsky's section on it in 'Dvoretsky's Endgame Manual'. Basically, you have the following key position, Black to move:

8/8/8/p4kp1/P7/6K1/8/8 b - - 0 1

This position is a draw, as if you count the race between Black getting to the b2-square (after first capturing the a4-pawn) and White reaching the drawing c1-square, White arrives just in time.

For every square the g-pawn moves back, the stronger side gains a tempo in the race (c1 vs. b2). For every square the g-pawn moves forward, the defending side gains a tempo in the same race (c1 vs. b2).

The other factor affecting the race is how far the a-pawn is advanced. So if we take the following position:

8/8/8/5kp1/p7/P5K1/8/8 b - - 0 1

Now it is Black who wins by a single tempo, reaching b2 when White's king is on d2. This means that, every square your pawn is advanced gains you a tempo in the race, whether you are White or Black.

ER
28-07-2020, 07:17 PM
Here is another page on Bähr's rule (http://fraserheightschess.com/Documents/Bahrs_Rule.pdf) with some exercises as well. In the QLD Champs 2017 thread (http://www.chesschat.org/showthread.php?16999-2017-Qld-Champs&p=430697&viewfull=1#post430697), Solo discusses a modified form where the defending K starts two ranks in front of the outside passed P, so the defending P must be a rank higher to draw.

What an extremely interesting concept in a position that often arises on otb and online games. Parallelly, another hidden treasure of Chess Chat's resources. The fact that Bahr is discussed here by so many strong players including a GM, an IM and a couple of FMs is definitely not coincidental!