Chess Problems: The Half-pin Theme
By David Friedgood
The concept of the half-pin is quite simple: “Two units are said to be
half-pinned [against the king] when one of them becomes completely pinned when
the other moves.” (John Rice, “Chess Wizardry: The New ABC of Chess
Problems”, B.T. Batsford 1996). The half-pin theme intensifies the richness
of the solving experience. It combines well with many other themes and motifs,
providing fertile ground for composers for well over a century.
1.Nd3 Nc4 1...Rc3 2.Qa4# 1...c5 2.Qxb3# 1...Bc5 2.Qxc5# 2.Nc3#
- Start an analysis engine:
- Try maximizing the board:
- Use the four cursor keys to replay the game. Make moves to analyse yourself.
- Press Ctrl-B to rotate the board.
- Drag the split bars between window panes.
- Download&Clip PGN/GIF/FEN/QR Codes. Share the game.
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K.A.K. Larsen | - | Mate in 2 | - | | 1921 | | Good Companions | |
Please, wait...
The first problem is a simple introduction. The half-pin structure is already
visible on the b-file: when the black rook or knight moves off this file the
other becomes pinned by the b1 rook. All we have to do to activate the half-pin
variations is to find the key move that will provoke the thematic defences.
The second problem shows a masterly treatment by a great exponent, combining
the half-pin with self-block, line-opening, interference, and unpin.
1.Qf5! Ne2 1...Nxd5 2.Qxf1# 1...Nb5 2.Nc5# 1...Qd3 2.Nd4# 1...Qxd2+ 2.Nxd2# 1...Qxb3 2.Bxb3# 1...Ng5 2.Rc5# 2.d3#
- Start an analysis engine:
- Try maximizing the board:
- Use the four cursor keys to replay the game. Make moves to analyse yourself.
- Press Ctrl-B to rotate the board.
- Drag the split bars between window panes.
- Download&Clip PGN/GIF/FEN/QR Codes. Share the game.
- Games viewed here will automatically be stored in your cloud clipboard (if you are logged in). Use the cloud clipboard also in ChessBase.
- Create an account to access the games cloud.
Comins Mansfield | - | Mate in 2 | - | | 1919 | | 1st Prize Hampshire Telegraph and Post | |
Please, wait...
The last two diagrams are for the reader to solve. In each case, you have to
find the unique key move for White, after which Black is unable to avoid mate
on the second move regardless of what the defender plays. In both cases the
half-pin is easy to spot and the variations are relatively simple, but the keys
are quite crafty. As a hint to the inexperienced solver, I would mention that
the key of a problem does not necessarily carry a threat.

Mate in two moves
Mate in two moves
Solutions will appear in approximately one week.
Any queries or constructive comments can be addressed to the author at david.friedgood@gmail.com.
Copyright in this article David Friedgood 2012/ChessBase
The
British Chess Problem Society (BCPS), founded in 1918, is the world's
oldest chess problem society. It exists to promote the knowledge and enjoyment
of chess compositions, and membership is open to chess enthusiasts in all countries.
The Society produces two bi-monthly magazines, The Problemist and
The Problemist Supplement (the latter catering for beginners), which
are issued to all members. Composers from all over the world send their problems
and studies to compete in the tourneys run by the society.
The BCPS also organises the annual British Chess Solving Championship, and
selects the Great Britain squad for the World Chess Solving Championship. The
Society holds an annual residential weekend, with a full programme of solving
and composing tourneys and lectures; this event attracts an international participation.
Members are also entitled to use the resources of the BCPS library, and the
Society book service, which can provide new and second-hand publications.