Week 103: what is a pin in chess? Two bishops on b5 explained it
A short weekend of chess, January 16 to 18, 2026: seven games, 4 wins and 3 losses, and my rating went from 1283 to 1292 (+9) after a dip to 1275 on the Saturday. The theme that kept appearing in the review was one of the first tactics every beginner learns, and I still get wrong: what is a pin in chess, and what happens when you ignore one. Twice this week a bishop on b5 decided things — once against me, once in a way I caused myself.
The week in numbers
| Games | 7 |
| Wins / losses / draws | 4 / 3 / 0 |
| Rating | 1283 → 1292 (+9) |
| Average accuracy | 81.2 % |
| Blunders | 10 |
| Openings | Modern Defense with 1 e4 (2), London System, Queen's Pawn Opening, English Anglo-Indian, Accelerated London, Nimzowitsch Defense (1 each) |
81.2 % is my best average in a while, and my four wins averaged 91.8 %. Two of them ended in checkmate on move 27: 27.Qc6# with White against SriHari1910 (1253) and 27...Qh2# with Black against HudsHeffer (1284). The three losses averaged 67.1 %, and eight of the ten blunders were in the middlegame.
A pinned knight: game 1961
A pin is when a piece can't move, or shouldn't, because a more valuable piece is standing behind it on the same line. If the piece behind is the king, the pinned piece can't legally move at all. Against SAHARA1945 (1274) I had Black in a Modern Defense, and on move 7 White put a bishop on b5.
Look at the diagonal from b5 to e8: bishop, my knight on c6, an empty d7, my king. The knight can't move. And White's knight on e5 is attacking it too. I played the natural developing move 7...Bg7, and the engine's punishment starts with 8.Nxc6, which also attacks my queen on d8 (+4.88, "white is winning"). The game went 8.d5 Nxd5 9.Nxc6 bxc6 10.Bxc6+ Bd7 11.Bxd5, and White came out with extra material. The engine's 7...a6 attacks the bishop and asks it to decide now; White is still clearly better (+1.90), but the damage is smaller. I won this game only because White was winning for most of it and then 27.Qc2 left the queen to 27...Qxc2, after which my opponent abandoned (game).
A defender that walked away: game 1960
The next pin-shaped moment was my own fault. With White against Robby-Lafadza-Yasin (1272) my bishop sat on b5, protected by my pawn on a4.
13.a5 looked strong: a pawn attacking the queen on b6. But position.py says what I missed — the pawn "stops defending the bishop (b5), which can now be captured". Black's queen just took it, 13...Qxb5 (−6.24), and the game was abandoned on that move. 13.Nc4 attacks the knight on e5 and the queen on b6 at once and keeps the game about equal (+0.23) (game). Every piece that defends something is pinned to its job in a quieter way: when it moves, whatever it was guarding becomes free.
Trading my king's bishop: game 1959
Against bhoypels (1291), another Modern Defense, I was clearly better on move 13 (−1.88).
13...Bxe5 even creates a double attack on the d4 bishop and the knight behind it, but the engine's line 14.Bxe5 Nxe5 15.Qh6 shows the cost: my fianchetto bishop disappears and White's queen lands close to my king, attacking my rook on f8, with the game now about equal (−0.02). With 13...Nc6 I stayed clearly better (−1.61). Later I was even winning (−4.96 on move 23), but White opened the h-file and 23...Kg7 walked into a forced mate; I was mated on move 27 (game).
The lesson of the week
Pins come in two shapes. The obvious one, like the bishop on b5 against my knight in game 1961: when a piece is pinned and attacked twice, deal with it immediately — attack the pinner (a6) or break the line. The quiet one, like my a4 pawn in game 1960: every defender is tied to what it defends. Before I move a piece, I ask what it is protecting right now.
All games this week
| Game # | Date | Colour | Opponent (rating) | Result | Opening | Accuracy | Link |
|---|---|---|---|---|---|---|---|
| 1958 | 2026-01-16 | White | eddiexxxtt (1277) | Win | London System | 93.7 | game |
| 1959 | 2026-01-16 | Black | bhoypels (1291) | Loss | Modern Defense with 1 e4 | 51.9 | game |
| 1960 | 2026-01-17 | White | Robby-Lafadza-Yasin (1272) | Loss | Queen's Pawn Opening | 70.0 | game |
| 1961 | 2026-01-18 | Black | SAHARA1945 (1274) | Win | Modern Defense with 1 e4 | 87.9 | game |
| 1962 | 2026-01-18 | Black | steakwad2001 (1412) | Loss | English, Anglo-Indian Queen's Knight | 79.4 | game |
| 1963 | 2026-01-18 | White | SriHari1910 (1253) | Win | Accelerated London | 90.5 | game |
| 1964 | 2026-01-18 | Black | HudsHeffer (1284) | Win | Nimzowitsch Defense, Williams | 94.9 | game |
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Frequently asked questions
What is a pin in chess?
A pin is when a piece can't move (or shouldn't) because a more valuable piece stands behind it on the same line. In game 1961 White's bishop on b5 pinned my knight on c6 to my king on e8, so the knight couldn't move.
How do you get out of a pin?
Attack the pinning piece or put something between. In game 1961 the engine's move was 7...a6, a pawn attacking the bishop on b5; I developed instead and White won material.
What happened to my rating this week?
It went from 1283 to 1292 (+9) in seven games, after dipping to 1275 on January 17.