user109: The same question applies to Black where the dark-squared bishop is considered Black's best bishop.
This was from the book "Logical Chess Move by Move" by Irving Chernev where he quotes Siegbert Tarrasch as saying the King's Bishop is the greatest attacking piece, so I guess it does pertain to mainly one player with one school of thought.  I found it interesting how Tarrasch at times would not even move his King's Bishop during a whole game.

user19877: I would not call it "white's better bishop", but it is considered crucial to a king-side attack in most cases. Without it, black can defend his king-side a lot more easily.
You have to consider that "Logical Chess Move by Move" is a very beginning-level book and is meant to show clear games, often between players of significantly different strengths, and many of the games are very old, from a time when king-side attacks were more commonly allowed. We simply do not think the same way today as defense is a lot better, but it is hard to get an attack on the black king without it...in general.
I only answered to post that rule of thumb about the light-squared bishop usually being crucial to an attack on the black king-side.

user69: I would say the values of the light-squared bishop vs the dark-squared bishop is negligible, but in any given opening, one is likely to end up more valuable.  It may be that if you average over -all- openings, the bishop that can attack f7 and h7 would be more valuable, but such averages are next to meaningless and counterproductive if you end in on of the 'exceptions' that happens 40% of the time.
For example, when black plays the French opening one of his bishops usually ends up being quite terrible, at least for a while.

user17: White's light (king's) squared bishop stands on squares of the color occupied by the enemy king. This is true of his initial position, e8, and his likely castled positions, mostly g8, occasionally c8.
Also, the light squared bishop attacks important squares around the enemy king. This includes f7 and d7 for both the original and castled positions (on the king and queen side respectively) plus h7 (king's side castling), or b7 (queen's side castling). 

user84: Neither bishop is inherently better than the other.  Depending on your choice of opening, white's dark-squared bishop can be far more valuable to him.

user101: The black king, will occupy e8 and g8 (before and after castling, respectively), both of which are white squares.  Also, the weakest point on the black kingside is f7, again a white square.  Because of this, if you are trying to attack the king, the white bishop can often be more valuable.  
Perhaps someone else can add some more deeper reasons, but this has been my experience.
Added: Also worth noting, attacks on h7 can often threaten mate, another white square.  Furthermore, just having the bishop on the diagonal attacking f7 would pin the pawn to a castled king.  

109: <p>The same question applies to Black where the dark-squared bishop is considered Black's best bishop.</p>

<p>This was from the book "Logical Chess Move by Move" by Irving Chernev where he quotes Siegbert Tarrasch as saying the King's Bishop is the greatest attacking piece, so I guess it does pertain to mainly one player with one school of thought.  I found it interesting how Tarrasch at times would not even move his King's Bishop during a whole game.</p>
 19877: <p>I would not call it "white's better bishop", but it is considered crucial to a king-side attack in most cases. Without it, black can defend his king-side a lot more easily.</p>

<p>You have to consider that "Logical Chess Move by Move" is a very beginning-level book and is meant to show clear games, often between players of significantly different strengths, and many of the games are very old, from a time when king-side attacks were more commonly allowed. We simply do not think the same way today as defense is a lot better, but it is hard to get an attack on the black king without it...in general.</p>

<p>I only answered to post that rule of thumb about the light-squared bishop usually being crucial to an attack on the black king-side.</p>
 69: <p>I would say the values of the light-squared bishop vs the dark-squared bishop is negligible, but in any given opening, one is likely to end up more valuable.  It may be that if you average over -all- openings, the bishop that can attack f7 and h7 would be more valuable, but such averages are next to meaningless and counterproductive if you end in on of the 'exceptions' that happens 40% of the time.</p>

<p>For example, when black plays the French opening one of his bishops usually ends up being quite terrible, at least for a while.</p>
 17: <p>White's light (king's) squared bishop stands on squares of the color occupied by the enemy king. This is true of his initial position, e8, and his likely castled positions, mostly g8, occasionally c8.</p>

<p>Also, the light squared bishop attacks important squares <em>around</em> the enemy king. This includes f7 and d7 for both the original and castled positions (on the king and queen side respectively) plus h7 (king's side castling), or b7 (queen's side castling). </p>
 84: <p>Neither bishop is inherently better than the other.  Depending on your choice of opening, white's dark-squared bishop can be far more valuable to him.</p>
 101: <p>The black king, will occupy e8 and g8 (before and after castling, respectively), both of which are white squares.  Also, the weakest point on the black kingside is f7, again a white square.  Because of this, if you are trying to attack the king, the white bishop can often be more valuable.  </p>

<p>Perhaps someone else can add some more deeper reasons, but this has been my experience.</p>

<p><strong>Added:</strong> Also worth noting, attacks on h7 can often threaten mate, another white square.  Furthermore, just having the bishop on the diagonal attacking f7 would pin the pawn to a castled king.  </p>
