Theme Palaestra

This month we are privileged to give the first part of Mr. Vincent L. Eaton's brilliant essay on an interference theme, in which he has done notable pioneering work. We believe it to be one of the most important and original contributions to creative thematic research within recent years, and recommend it to all who enjoy a clean-cut and spectacular theme.

NOTES ON AN INTERFERENCE THEME By Vincf.nt L. Eaton

These notes are (he result of a number of recent experiments by the writer in the field of Black interferences and cross-checks. The basis of the theme which we are about to discuss is an interference maneuver by Black which allows the White king to move to a previously-guarded square. Thus, in the two-mover, No. 984, if 1 . . . Rd3ch; 2 Kc2 mate or 1 . . . Rd4; 2 Kb2. In No. 985 the moves 1 . . . Sc6 or 1 . . . Se6 are interceptions of the Black rooks which allow the White king to move to c7 and e7, respectively. With the aid of an obtrusive White bishop, five distinct interferences of this type can be shown (No. 986) and the maximum of six seems quite possible of attainment.

A three-move extension of this idea consists in having the Black piece which performs the interference move again, thereby discovering check from the intercepted piece, and producing a fireworks display of checks and counter-checks. No. 987 is perhaps the earliest example to he found in problem literature, after 1 Be7 (the key) the move 1 . . . Sc4ch interferes with the Black bishop's guard of b5, allowing 2 Kb5ch, whereupon 2 . . . Sa5ch reopens the line and 3 Sol mate results. More recent examples are Nos. 988, 989, and 990, the latter two being doublings of the idea. Castling maneuvers may also be employed, as in No. 991, wherein the defense 1 . . . Rd4 cuts off Black's guard on the square gl. Finally, in No. 992, the White King takes an even more active part in the play by unpinning the White piece which performs the theme mates.

The final step in the evolution of my idea is the addition, on Black's second move, of an interference unpin of a White piece. To restate it succinctly: Black performs two successive interferences; the fir it allows the White king to move to a previously-guarded square; the second, discovering check, is an interference unpin of a White piece which mates by interposing.

Thus, in No. 993, after 1 Qe8, the move 1 . . . Se5ch releases the square h5 for the White King, and after 2 Kh5ch, the line is reopened by 2 . . . Sg4ch; this, however, blocks the line dl-h5 and allows the unpinned White knight to mate at g5. No. 993 was the first rendering of the complete theme, and as a search of the A. C. White Problem Collection has indicated, perhaps the only version prior to the writer's experiments.

Examples of the theme can be divided into four classes, depending on whether they illustrate:

1. A lateral, followed by a diagonal, interference.

2. A diagonal, followed by a lateral.

3. Two successive lateral interferences.

4. Two successive diagonal interceptions.

Type 1. Lateral, followed by diagonal, interference. Of the four types, this is by far the most flexible, and under this heading belong Examples Nos. 993-1005. The first six show the scheme with unpin of a White knight. No. 994 adds a Black half-pin arrangement and a changcd mainplay, while No. 995 is a simple setting with quiet play on Black's first move. Solvers may recall the writer's Honor Prize problem in the February Chess Review, which has a White knight unpinned on a different square with relation to Black's king; and other types of knight unpin may be obtained by using a diagonal rather than a lateral Royal battery, as in Nos. 996 and 997. The latter shows the White knight at the farthest possible distance from the Black king.

No. 998 employs castling to produce an unpin of the same nature as that shown in Nos. 993, 994, and 995. Here, the double step of the White king has technical interest in that it pins the knight on the line g5-cl, preparing for its subsequent release.

Nos. 999 and 1000 are other castling examples, utilizing a bishop and a queen, respectively, in the unpin play. In No. 999 also, a White knight or queen may be used in place of the Bishop, but one example will suffice. So far as the interference theme is concerned, the castling maneuver is of little value; it is equivalent to the White king's uncovering a Royal battery check by moving from d2 to cl, in response to an interception of Black's guard of cl.

Nos. 1000-1003 illustrate unpin of the White queen at various loci. No. 1001 has a thematic change-play: as set, if 1 . . . Sf5ch; 2 Kf2ch, Se3ch; 3 Qf6 mate. This is altered to a queen mate at f5. No. 1002 uses a diagonal, rather than a lateral. Royal battery, with one square intervening between the two kings. Two squares separate them in:

V. L. E. Chess Review. Nov. 1937: BBlblr2, 2p2p 2, 2K5, pQ6,b7, IsRrlkPP, 3PR2P, lqS5. Mate in three. (1. Ba7.)

No. 1003 shifts the battery three squares distant, and No. 961 in the March Chess Review carries it four squares away—as far as can be done.

We may conclude this section with Nos. 1004 and 1005, the first illustrating unpin of a White Pawn, the second showing the possibilities resulting from combining the interference theme with other strategic motives. To the simple knight unpin of No. 996 arc added a complete Black half-pin arrangement, double-checking. White self-unpinning, direct unpinning by Black, and Black self-pinning—showing what happens when restraint is tossed aside.

In the concluding article I shall deal with the three other types of consecutive interference, doublings of the theme, and a number of tactical variations which have suggested themselves. Meanwhile, I should be very glad to hear from any composers who care to experiment along these lines.

Washington, D. C.

Original Section

(Original) (Original) (Original)

Covington, Ky. Wednesbury, England Washington, D. C.

Mate in 2 Mate in 2 Mate in 2

(Original) (Original) (Original)

JOHN HANNUS SIMON COSTIKYAN V. L. EATON

Los Angeles, Calif. New York City Washington, D. C.

Mate in 2

Mate in 3

Mate in 2

No. 981 ( Original) C. S. KIPPING Wednesbury, England

Wiener Schach-Zeitung May 1935

No. 987 W. GREENWOOD

Caswell's Weekly Magazine 1857

Mate in 2 Mate in 2 Mate in 3

SOLUTIONS TO THESE PROBLEMS ARE DUE MAY 10th, 1938

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