Good and bad bishops

When I hear the terms good and bad bishops, it often seems to come without any debate: the good bishop is the one not encumbered by its own pawns being stuck on the same color (thus blocking the bishop) and with pawns from the opponent on the same color as the bishop (thus possible preys for the bishop). This makes good sense to some extent but that doesn't seem to always hold true. First, pawns aren't locked forever: they do end up moving, turning the good bishop into a bad one and vice-versa! Second, there seems to be counter arguments for valuing having a bishop and pawns of the same color in an end game since they can defend each other quite well: they can for example lock some columns and rows that would otherwise allow an adversarial rook to have counter play, the bishop can defend a few pawns at the same time and be protected at the same time, etc.

So are there some more subtle positioning guidelines regarding the placement of pawns when one has one bishop left? Or does having pawns the opposite color to the bishop remain the rule to follow no matter what? Note I am asking about strategy considerations here; not specific tactical situations that would call for positioning pawns a certain way to obtain an immediate gain.

Good question. I've never explicitly read or heard this, but my understanding is that the colors controlled by the pawns should change between middlegame and endgame, if the position requires it. In the middlegame you *don't* want your bishop and pawns on the same color because the pawns block the bishop, but in the endgame you *do* want your pawns on your bishop's color so your bishop can protect them, especially in endgames with opposite colored bishops. I encounter that type of endgame a lot with the openings I play, and there is often a period of the early endgame where I shift my pawns onto the protectable color, if I haven't done so already.

If you're really interested I can post some quotes from books that give exactly the opposite advice about this, which is partly what leads me to my conclusion, and I can post some games I've played against the computer that demonstrate how and when I shift my pawns, and how I win when the computer doesn't. It will take some time to look those up, however.

I think the real question, though, is whether all bad bishops go to Hell. 

Nothing about bishop colors in either link. Did you even understand the OP's question?

Like every chess question, it depends on the position.  

 One main factor of a bad Bishop is having a locked center pawn of the same color.  This can greatly affect the mobility of the Bishop at all stages of the game.  If the pawn is isolated then it can be a liability that the Bishop has to guard, also.   

Another factor of having a bishop on the same color as pawns, is that it can leave you weak on the other color of squares.

So, when looking at just these 2 factors you have to weigh whether your Bishops mobility is bad or can you find a good diagonal for it.  And, can your opponent make use of the opposite color squares, for example using then as outposts or invasion points.  If your opponent cannot make use of the other color complex it isn't that bad for you.

It's really a shame this is not more well known. Even beginners know things like control the center, castle, rooks like open files, knights on outposts etc, but in the endgame you don't want your bishop and pawns on the same color.

Are there exceptions? Of course, but in most positions it's a very useful rule to follow. There are 3 very common sense reasons:

1: The bishop's mobility is decreased if pawns occupy its color.

2: Pawns on one color tend to result in the opponent's pawns being on the other color. So your bishop will not only be immobile, but totally passive as there's nothing for it to attack. In an endgame this is even worse because a single piece can represent most of your potential for activity.

3: Abandoning the other color allows the enemy to use those squares for infiltration. Infiltration squares allow the opponent to attack all surrounding squares. So a light square weakness is not solved, for example, by placing everything on dark squares as some new players think, the opponent will use the light squares as outposts to attack any dark square they wish.

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An exception to this very good rule of not placing pawns on the same color as your bishop in the endgame, is when you're using your pawns to restrict the enemy (usually in cases where you have a big space advantage). Sometimes certain arrangements of pawns really kill the opponent's knight, or king, for example. So even though your bishop is relatively immobile and passive, you can use your king activity / pawn breaks to win anyway.

The other exception is in opposite color bishop endgames where you're setting up a fortress. This type of fortress doesn't do well in other endgames as I explained (infiltration squares allow enemy pieces to attack all surrounding squares). But in opposite color bishop endgames this isn't as true (bishops only ever attack one color), so it's sometimes a good way to draw.

 Wrong.

This is an exception.

True, but a game between equal players will rarely have one player with a mobile pawn center. Through the meat of the game the center pawns are fairly fixed.

But also, some "bad" bishops are active, and so it's not a problem. Usually this is because they've moved outside of their pawn chain. The first example that comes to mind is a position from a london opening.

In such a case when the pawns advance it may not have much impact on the value of the bishops.

Anyway, in general this is what makes a piece valuable:

1) mobility / how many squares it's influencing.

1.5) Central squares tend to be more valuable because you can shift to either side more easily as needed.

2) Having the potential to, at some point, come into contact with weak pawns (or assist in a king hunt). Especially in the endgame you'll notice that pieces without this potential feel totally useless as the game goes on. (and of course the sooner they can the better. A knight that need 6 moves to attack a pawn is not very useful as you might imagine).

3) They aren't easily harassed by the enemy e.g. a pawn attacking a knight forcing it to move, or if the piece is undefended, so it's vulnerable to tactics.

I had asked for an explanation of this in a previous thread maybe a few years ago and someone mentioned that the term "good" and "bad" bishop should be replaced with "active" and "inactive" instead since technically you can have a "good" bad bishop if it's outside the pawn chain. 

This may also assist in answering your question. The value of a Bishop can usually be assessed by the following rule: the Bishop has good working power if its own pawns are posted on squares of the opposite colour. This of course applies only where the pawn formation cannot easily be altered. The differing value of Bishops is an important strategical factor. As a rule, each side will endeavor to place his own pawns on a colour opposite to that of his or her Bishop; this makes it easier to block the opponent's pawns on squares accessible to the Bishop. When the position has become simplified and the pawn formation fairly rigid, both sides will try to rid themselves of a bad Bishop and keep a good one. In the middle-game it is sometimes possible to initiate a series of exchanges leading to a favourable end-game of good/active versus bad/inactive Bishop. This rule for determining whether the Bishop is good or bad must be modified in certain circumstances. For e.g. 1. d4 d5 2. c4 c6 3. cxd5 cxd5 4. Nc3 Nc6 5. Nf3 Nf6 6. Bf4 Bf5 7. e3 e6, the Bishops on f4 and f5 can hardly be called bad/inactive, although they are the same colour as their own blocked pawns; their position outside the pawn chain makes a difference, and, in fact, they can develop great strength. After 8. Qb3 Bb4 in the game Botvinnik-Trifunovic Moscow 1947, Black exchanged his 'good' Bishop on b4 against White's Knight on c3, but nevertheless got a good game on account of the active position of his other minor pieces.