Good bishop, bad bishop

The key idea

Pawns fixed on your bishop's color = bad bishop (goalkeeper for its own pawns). The good bishop attacks what the bad one is condemned to defend — and when there are two weaknesses and one defender, the arithmetic does the rest.

Example 1 · The good bishop's harvest

Black's pawns on b5, d5 and g6 live on light squares — the color of Black's bishop. Count the weaknesses, count the defenders, and watch what happens.

1. Bxg6 The arithmetic of the bad bishop, in one move: the bishop on d7 was tied down to watching b5, so g6 was left without a guardian. With two weaknesses on light squares and only one defender, one always falls. If the bishop had run to e8 earlier to save g6, b5 would have fallen on the other side.
2. Bg4 Black's bishop finally leaves its cage, looking for activity on the other side. It's the best it has — standing guard no longer saves anything — but it's too late: the house is on fire.
3. Kxd5 Second course, same pattern: d5 also lived on a light square and its bishop is no longer there to defend it. Notice the underlying detail: EVERYTHING Black planted on its bishop's color has turned into food.
4. Bd1 Black's bishop wanders looking for something to bite. There's nothing: our pawns on b4, d4 and h4 stand on DARK squares, forever out of its reach. That's the other half of the rule.
5. Kc5 The king heads for the third weakness, b5. No need to rush or calculate finely: Black has no counterplay, only watching.
6. Bb3 Watches from afar, unable to bite anything that matters.
7. d5 Sound familiar from another lesson? Passed pawn. The d4 pawn was freed when Black's d5 pawn disappeared, and now it runs. And there's a poisonous detail: it queens on d8, a DARK square — the light-squared bishop will never be able to touch it.
8. Kf6 Black's king runs to stop the pawn. One of the pawns, rather.
9. h5 Because there's another one: the h-pawn also became passed once g6 fell. Two passed pawns on opposite wings, both queening on a dark square, and a bishop that can't touch either highway.
10. Ke7 The king chooses to watch the d8 promotion square. It's the right call — and it's not enough: no one is left for the h-pawn.
11. h6 Game decided: the h-pawn either queens or takes down the last defender who tries to chase it, while d5 advances escorted by its king. Look at the starting position again: exactly the same material. The entire difference was in six pawns — Black's stuck on its bishop's color, White's safe on the other. That's what having a good bishop means.

Example 2 · The same pattern, with the colors swapped

Mirror position: now the good bishop is BLACK's, and the badly placed pawns are White's. Recognize the pattern — the rule has no color and no direction.

1. Bxg3 The same arithmetic as example 1, seen from the other side: White's bishop on d2 was tied to defending b4, and g3 — a pawn on a dark square, the color of Black's bishop — was left without a guardian.
2. Bg5 White's bishop looks for air on the other side, just as Black's did in the mirror.
3. Kxd4 Black's king harvests on the dark squares. If you were counting the pattern in the last example, here you should be singing it before it happens.
4. Bd8 A walk to nowhere: Black's pawns on b5, d5 and h5 live on light squares, invisible to this bishop.
5. Kc4 The king, heading for b4. Third weakness, zero possible defenders.
6. Bb6 Watch and wait. There's no more role left for the bad bishop.
7. d4 The passed pawn, queening on d1: a LIGHT square, off-limits to the dark-squared bishop. The mirror is perfect.
8. Kf3 White's king runs toward one of the fires.
9. h4 And the second passed pawn starts marching on the other wing.
10. Ke2 Off to watch d1. No one will watch the h-pawn.
11. h3 Decided, again. If you recognized every move before seeing it, the lesson is done: you didn't memorize a game — you learned to READ where the pawns live. That reading decides which bishop is worth a piece and which is worth a single extra pawn, in any position you come across.

Practice

You play White in the first example's position. Same material as your opponent — and a game won purely on bishop quality. Carry out the harvest: count the weaknesses, eat on light squares, and launch the passed pawns.

1. Exact arithmetic: Black's bishop was watching b5, so g6 was on its own. Two weaknesses, one defender — one always falls. Two black pawns live on light squares (b5 and g6) and only one bishop watches them. Which one lost its guardian? Eat it.
2. The king also harvests on light squares. Everything Black planted on its bishop's color is food. Your king has an undefended pawn one step away, on a light square, of course. Go for it.
3. On the way to the third weakness. No rush: the opponent has no counterplay, only a bishop stroll. One more weakness remains on a light square: b5. Bring the king closer.
4. Passed pawn — queening on d8, a dark square, where the enemy bishop will never exist! The passed-pawn lesson, applied. With Black's d5 pawn gone, one of your pawns has an open file. Launch it.
5. The second passed pawn wakes up: g6 fell and the h-pawn has a highway. Two passed pawns on opposite wings — every book's favorite endgame. Look at your h-pawn: ever since g6 fell, it's passed too. Set it in motion.
6. Game decided: Black's king watches d8 and no one is left for the h-pawn, which queens on h8 — a dark square too. The bad bishop ends the game the way it started: watching. Black's king went to watch the d-file promotion. Push the h-pawn: its bishop can't touch h8.

The good bishop's harvest, signed by you: three pawns on light squares turned into two unstoppable passed pawns. From now on, when you trade pawns or choose where to plant them, you'll look first at the square color — because you've just felt in your own hands what it costs to get the color wrong.