Problem World > No.24
Classics by Peter Wong

In this final instalment of Problem World, we focus on six problems of various genres that are recognised as classics. A ‘classic’ problem indicates a renowned piece of work that has an enduring appeal. Such a composition typically shows striking and original play, as well as displays skilful construction. Some classics are of historic interest for being the first expression of an important theme; others are famous for their outstanding rendition of a known idea.

139. Otto Wurzburg
British Chess Magazine 1896
Mate in 3

The three-mover 139, an economical miniature, begins with a marvellous withdrawal key, 1.Bh3! The object of this move is line clearance: after 2.Qg4 (the threat), the queen has access to the mating squares c8 and d7. For example, 1…e4 2.Qg4 K-any 3.Qc8, 1…Kc7 2.Qg4 Kd8 3.Qd7. This type of line clearance is called a Turton manoeuvre, since the queen moves in the opposite direction from the line-clearing bishop (compared with a Bristol clearance, in which both thematic pieces move in the same direction). Black has one defence, 1…a5, that foils the threat by preparing for 2…a6. White responses with a queen sacrifice 2.Qa6+ Kxa6 3.Bc8, finishing with a model mate.

140. Arnoldo Ellerman
Guidelli Memorial Tourney 1925
1st Prize
Mate in 2

Elegant battery play and attractive subsidiary variations are the features of Problem 140. After 1.Rd7! to guard d3, White threatens 2.Qf4, and this draws the black queen away from the pin of the white knight. In two of the main lines, 1…Qe5 2.Sc5 and 1…Qd4 2.Sd6, the queen’s self-blocks allow White to fire double-check battery mates, in which the knight self-interferes with a white rook’s line of guard. 1…Qf2 compels 2.Sd8, when White must avoid the self-interferences. 1…Qh8+ is also met by 2.Sd8, and 1…Qxb7+ by 2.Bxb7. Three other black pieces provide the excellent by-play: 1…Bf2 2.Qxh1, 1…Bf3 2.Qd3, and 1…Rd4 2.Re7. Furthermore, the subtlety of the key is underlined by a number of alternative placing of the key-rook, tries that are refuted by unobvious queen defences: 1.Rd8? Qf2!, 1.Rd6? Qd4!, and 1.Rd1? Qd2!

141. Comins Mansfield
Die Schwalbe 1956
1st Prize
Mate in 2

The masterful 141 utilises an arrangement of pieces named an organ pipe, comprising Black’s pairs of rooks and bishops positioned in a row (as seen on the h-file). Such a set-up leads to four potential pairs of Grimshaw interferences. For example, one pair of Grimshaw occurs on g4: 1…Bg4 2.Qxe4, and 1…Rg4 2.Qd1. If White actively places a piece on g4 to induce both interferences simultaneously, the tactic is called a Novotny and its recurring use constitutes the main theme of this problem. Thus, the try 1.g4? generates the double threats of 2.Qxe4 and 2.Qd1, and if Black captures the pawn, each mate is forced individually: 1…Bxg4 2.Qxe4, 1…Rxg4 2.Qd1. But 1…Sxf2! successfully disables both threats. A second Novotny try, 1.g3?, shuts off the h3-rook and h2-bishop, to threaten 2.Qe3 and 2.Bxb3, and it is defeated only by 1…Sc2! The third thematic try is 1.f4?, which threatens 2.Qxe4 and 2.Bxb3. Black’s reply 1…e3! cleverly prevents both mates, by impeding the white queen and creating a flight on e4. The final Novotny move 1.f3! is the key, and it threatens 2.Qe3 and 2.Qd1. These mates are separated by 1…Bxf3 2.Qe3 and 1…Rxf3 2.Qd1. Impressively, the other black rook and bishop also come into play directly, when they move to f4 to cut off the white bishop’s control of e3, and thus stop both threatened mates. The result is an actual pair of Grimshaw variations, 1…Rf4 2.Bxb3 and 1…Bf4 2.Qxe4. Also, 1…Kd4 2.Qxc3.

142. Sam Loyd
London Era 1861
Mate in 5

In the more-mover 142, the thematic white mate is delivered by perhaps the least likely piece on the board. If White were start with 1.Rd5? or 1.Rf5? to attempt mate on the first rank, the pinning 1…Rc5! would refute. The key 1.b4! attacks c5 and hence does threaten 2.Rd5 or 2.Rf5, and Black’s best defence is still 1…Rc5+, to intercept the white rook. Now 2.bxc5, with the threat of 3.Rb1, forces 2…a2. White continues with 3.c6 to threaten 4.Rd5 or 4.Rf5 again, and Black’s response 3…Bc7 handles both rook moves adequately (4.Rd5? Bxg3!, or 4.Rf5? Bf4!). But this bishop defence commits the error of obstructing c7, which locks in the knight on a8. Consequently White is able to play 4.cxb7, followed by the unavoidable 5.bxa8(Q) mate. The motto of this problem, “Excelsior”, has become a general term to describe a pawn that begins on its original rank in the diagram and proceeds to promote during the course of the solution.

143. Henry Forsberg
Revista de Sah 1936
1st Prize
Helpmate in 2
(b) BRa6
(c) BBa6
(d) BSa6
(e) BPa6

In the five-part helpmate 143, the various starting positions are brought about by homogenous twinning. By replacing the queen on a6 with every other kind of black piece in turn – rook, bishop, knight, and pawn – we produce four new settings, each with a distinct solution: (a) 1.Qf6 Sc5 2.Qb2 Ra4, (b) 1.Rb6 Rb1 2.Rb3 Ra1, (c) 1.Bc4 Se1 2.Ba2 Sc2, (d) 1.Sc5 Sc1 2.Sa4 Rb3, and (e) 1.a5 Rb3+ 2.Ka4 Sc5. The five phases of play are harmonious and yet nicely varied, such as the way the black pieces all self-block but do so on different squares. The construction is flawless in its economy, including the well-placed white king used to prevent cooks in part (b), e.g. 1.Ra5 Sc1 2.Ra4 Rb3, disabled only by the pin of the rook.

144. Julio Sunyer
Chess Amateur 1923
White and Black retract 1 move,
then helpmate in 1

Problem 144 belongs to a problem type known as retractors, and it represents one of the most famous works from the unorthodox fields. The solver is asked to take back a white move, then a black one (any legal retraction is allowed, the two sides cooperating), so as to arrive at a position that permits a helpmate-in-one to occur. Retraction play gives rise to concepts such as ‘uncaptures’ and ‘unpromotions’, and the former is clearly required in this case, since White will need a piece uncaptured by Black for delivering mate. It transpires that a black piece is also uncaptured by White, used for self-blocking and another, more surprising, purpose.

Problem 144 solution (To display, hold down your mouse button and select the text below.)

> Retract 1.Kg6xRh5 Rh8xQh5, and then play 1.0-0 Qh7 for the helpmate. A castling move remarkably lies hidden in the perfect setting of two kings only.