The Novotny is a device found in chess problems named after a problem from 1854 by Antonín Novotný, though the first example was composed by Henry Turton in 1851. A white piece is sacrificed on a square where it could be taken by two different black pieces - whichever black piece makes the capture, it interferes with the other. It is essentially a Grimshaw brought about by a white sacrifice on the critical square. This pattern can arise as part of a combination in an actual game, but it is extremely rare. Most chess players would not use the term "Novotny" to describe such a move, since that term is almost exclusively used in the context of chess problems.
Examples
Basic
The device can be understood by reference to the problem to the right, a mate in two moves. The key is 1.Nb2. This interferes with black's rook and bishop, and whichever of those pieces takes the knight, it will interfere with the other—this is the Novotny idea at its most basic. So, if black plays 1...Bxb2, this interferes with his rook and allows 2.Qf2#, while if he plays 1...Rxb2, it is the bishop that is interfered with, allowing 2.Qd4#. Problemists would generally agree that a single Novotny with no other play, as in this example, makes for a relatively uninteresting problem. Usually, Novotnys are combined in problems with other ideas, or several Novotnys are shown in a single problem.
Multiple Novotnys
The problem to the left is very well known. It contains no fewer than six separate Novotnys. It is by R. C. O. Matthews, was published in the British Chess Magazine in 1957 and won the Brian Harley Award. It is a mate in 3. The key is 1.b4, threatening 2.Bxb1 and 3.Ra3#. Black has six thematic defences, each of which White meets with a Novotny on move two:
1...Bb6 threatens 2...Ba5, interfering with the path of the white rook to a3. White counters with a Novotny interference: 2.Rd5. This interferes with the black rook on h5 and the bishop on a8, and so threatens 3.Nb5# and 3.Ne4#. Black can prevent one by capturing on d5, but not both, because the capturing piece interferes with the other.
1...Rbxb5 threatens 2...Ra5 stopping the threat. White can now play 2.Qd5 with the same interferences and threats as follow 1...Bb6.
1...Bc5 threatens 2...Bxb4 to defend a3, stopping White's threat. White counters with 2.Rb7, interfering with the bishop on a8 and the rook on b8 and leading to the same threats and comparable continuations as follow 1...Bb6.
1...Bb7 threatens to capture the white rook which would give mate. White can now play 2.Rc5 interfering with the bishop on a7 and the rook on h5, and so threatening 3.Nb5# and 3.Bxd4#. As before, a capture on c5 stops one of the threats, but not both.
1...Bd5 threatens 2...Bxc4, after which Black could meet white's threatened 3.Ra3 with 3...Bb3. White instead plays 2.Rbb6 with the same threats and variations as follow 1...Bb7.
1...Rhxb5 threatens 2...Ra5, stopping the threat. White instead plays 2.Rb6 with the same threats and variations as follow 1...Bb7.
Four of White's Novotnys in these variations are executed by the rook on b5—only the rook will do in those variations, because the square it comes from, b5, must be vacated for the white knight to deliver mate. In the other two lines, that rook is captured, meaning it cannot execute the Novotny, but also meaning the square vacation is no longer necessary. Therefore, another piece can make the Novotny interference in those lines.
As part of a larger scheme
Many problems include a Novotny as part of some larger scheme. The problem to the right, by Milan Vukcevich, published in Schach-Echo in 1976, includes a Novotny as just one part of a more complex problem. It is a mate in 2. The key is 1.Qd6, which is a Novotny interference with the black rook and bishop on b8, so threatening 2.Ne5# and 2.Nxd2#. After the capture of the queen by the rook or bishop, the other black piece is still interfered with by the capturing unit; so 1...Rxd6 rules out 2.Nxd2 but still allows 2.Ne5#, while 1...Bxd6 rules out 2.Ne5 but allows 2.Nxd2#. Just as these Novotny lines work as a pair, so the other black defences work in pairs:
The Novotny theme in practical play
The Novotny theme occurs extremely rarely in actual play. The strong English masterAmos Burn produced such an example in an offhand game in 1910. In a seemingly desperate position, with his king apparently about to fall to a powerful attack by White's pieces, Burn played 33...Qg4!! The point is that if the bishop or pawn takes the queen, the white rook's pin on the black bishop is lifted, allowing 34...Bxd2; if the rook takes the queen, the white bishop no longer protects f3, so Black can play 34...Nf3+ and 35...Nxd2. Finally, if 34.Qxg5+, Qxg5 35.Rxg5+ Kh6 wins a piece. Burn won in 15 more moves . In the position at right, from Rubtsova-Belova, USSR 1945, White has just played the attractive-looking 1.Rf4-g4? Black cannot capture the rook, and White would win a piece after 1...Qf6? 2.Rxg3. However, Black responded with a decisive Novotny, 1...Ne2+! This enables Black to win the rook after 2.Rxe2 Qxg4; 2.Bxe2 Qxe3+ and 3...fxg4; or 2.Kf1 Qxg4. Black won. The Novotny theme could also have occurred in actual play in E. Berg-J. Zezulkin, Rowy 2000. From the diagram at left, White could have won with 40.Nf6!!. After 40.Nf6!!, White would threaten the two thematical mates 41.Qg7# and 41.Qf8# and in addition 41.Rg8# and 41.Qxh7#. Now 40...Bxf6 would block Black's rook, allowing 41.Qf8#, while 40...Rxf6 would block Black's bishop, allowing 41.Qg7#. After 40...Qxh6 which parries both thematical threats White has 41.Rg8#. The Novotny theme was played in David Navara vs Anna Dergatschova-Daus, Ordix Open, Mainz, 2007. If White could check on the a2–g8 diagonal, it would force mate quickly. But the R guards e6, and the B guards d5. So 36. Rc6!! intersects both lines: 36... Rxc6 37.Qd5+ Re6 38.Qxe6#, or 36... Bxc6 37.Qe6#; and if 36... Qxc6 then 37. e8=Q+ Qxe8 38. Qxe8#
