Bad bishop
A bad bishop is one whose own pawns stand mostly on its color, where they block its diagonals, leaving it with little range and few targets to attack.
The word bad describes a relationship between a bishop and its pawns, not the quality of the player. Every bishop is stuck on one color, so each pawn of yours on that color is a wall in front of it. When most of your pawns stand on the bishop's color, it ends up biting on its own chain and sees two or three squares and little else.
The French Defense is the standard source. Black's pawns on d5 and e6 stand on light squares and shut in the light-squared bishop on c8, which can easily spend the middlegame guarding pawns. Bad does not mean useless, though. The bishop still protects pawns and squares, and good players treat it as an asset to be repaired.
There are three repairs. Trade it, ideally for an enemy minor piece that matters. Reroute it outside the chain before the pawns lock it in. Or change the structure with a pawn break so the diagonals reopen. Leaving it where it is and hoping is not on the list.
Think of the reverse as well. If your opponent has the bad bishop, keep their pawns fixed on its color and avoid trading your better pieces for it.
A neighboring idea is Knight versus bishop. Knight versus bishop describes positions where one side has a knight and the other a bishop; the better piece depends on the pawn structure, favoring the bishop in open play and the knight in closed positions.
Compare it with Same-colored bishops. Same-colored bishops are bishops that move on the same shade of squares, so they can challenge, exchange and defend against each other, and an extra pawn is usually much easier to convert than with opposite colors.
A neighboring idea is Slav structure. The solid Black setup with pawns on c6 and d5 that supports the center while keeping the c8 bishop free to develop outside the pawn chain, usually on f5 or g4.
Strategic ideas such as "Bad bishop" show up in your games as small decisions, move after move. A first lesson with George Li reviews those decisions and turns them into a study plan.
Related terms
A good bishop is one whose own pawns mainly stand on the other color from the squares it travels on, so its diagonals stay open and it can reach the enemy camp.
The bishop moves any number of squares along a diagonal, as long as no piece stands in the way, so each bishop stays on one color of square for the entire game.
A pawn chain is a string of friendly pawns on a diagonal, each guarded by the pawn behind it, so only the rearmost pawn, the base, lacks pawn protection and becomes the usual target.
A color complex is a group of squares of one color around a king or pawn structure that turns weak when the defender has traded the bishop that guards them and left pawns on the opposite color.
Knight versus bishop describes positions where one side has a knight and the other a bishop; the better piece depends on the pawn structure, favoring the bishop in open play and the knight in closed positions.
Piece activity describes how much influence a piece exerts, measured by the squares it controls, the targets it eyes and the freedom it has to move, so an active piece is worth more than its nominal value.
Openings where it occurs
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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A game review, a read on your level and a written study plan from George Li.
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A first lesson starts with your games: George reviews them and builds a study plan around what he finds.