Well, the entry for VC's 1st Theme Tourney is now in, and while I am having the fun of going through the many interesting submissions, your Problem Editor has asked me to provide a small selection of other two piece problems, for your enjoyment.
Since being invited to judge, I've managed to find a surprising number of other problems — about 150 so far, without examining more than a couple of sources exhaustively. Some of this selection might have had prizes, had they been eligible; I've thrown in a few by other composers, too!
The obvious theme to show with few men is the echo, and (A) is a very simple example.
(A) H. Ebert & H. Axt
Four Men Only No. 2
Helpstalemate in 2 with set play
No Captures. Nightrider
The condition used here is partly to stop cooks and partly used to give the stalemates themselves. Often, the conditions are just pure cookstoppers, but I think this breach of economy is more acceptable in 2-man problems, considering the lean use of force! Also, 64 squares is rather a large place for just 2 pieces, and some way must be found of adding enough features to make sure the solutions aren't riddled with duals.
Another way of adding landmarks to the terrain is with a condition such as Circe, or its relatives, which give special merit to certain particular squares. This is the case in (B); I have added the last 3 parts which are ‘cousins' with 3 changes each. Again, I think some leeway must be allowed in such cases. There are echoes down the a-file here; can anyone find conditions to fill in the gaps?
(B) J. Mintz feenschach 1983
(b-d) S. Emmerson original.
Helpmate in 5½ Circe.
(b) bKe8 H‡4 Mirror Circe.
(c) bKd8 H‡5 Equipollent.
(d) bKa2 H‡2½ Antipodean.
In Circe, a captured piece other than a King is replaced on its home square if vacant, so if wSb3×Bd4 the B is added at f8. In Mirror Circe: a captured piece is reborn on the home square of a similar piece of opposite colour (Bc1); In Equipollent play a captured piece is displaced the same distance and direction as the move made by the capturing piece (Bf5); In Antipodean Chess a captured piece is reborn 4 ranks and 4 files away (Bh8).
If the pieces aren't enough, the conditions can become everything, as in the following task (C). The piece on f4 can change to any piece from S, B, R, or Q after each move, or not change at all, and the hypervolage condition means that every time a move finishes on a square of a different colour from that upon which it started, the piece will change colour as well. The Berolina pawn moves diagonally and captures straight forward; this is the piece to be mated. Finally, both sides must play a geometrically longest move. This problem shows that it's possible for pieces of the same side to mate, perhaps this example will encourage others to come out!
(C) M. Caillaud
Die Schwalbe 1980
Helpmate in 2.
Royal Berolina Pawn d3
In (D), I was fortunate to find an echo with correspondence in the play, in good modern style. Note the dual avoidance on W's 1st!
(D) S. Emmerson original
Helpmate in 2, 2 solutions.
The Querquisite can be thought of as a type of Chameleon; it has the power of movement of the piece upon whose file it stands, e.g. a rook on the a- and h- files, a king on the e-file, &c. Here both pieces are royal and can pass through check. The piece was invented by J. E. H. Creed, FCR June 1947 (and, as the Odysseus, by H. Schmid 10 years ago).
Another way to deal with few pieces rattling around in a large board is to add some force! (E) does this by the expedient of retracting the capture of the piece required to mate. In Grid chess, all moves and checks must cross a grid line.
(E) A. H. Kniest
Frankfurter Notizen 1966
Grid Chess. Black retracts one move for Serieshelpmate in 5
(b) move bK to square upon which it is mated in part (a)
(F) H. Ebert feenschach 1979
version by S. Emmerson
Help double stalemate (a) in 4
(b) in 5 exactly
(G) U. Marks
White Camel d3 = (0,1,3)-leaper, Black Ph4.
Stalemate in 3 with set play.
Stereo Chess (see VC 16).
Returning to adding force, here's a curiosity (H) in which this is done to help achieve a double stalemate!
(H) G. Busing
Remanantes Schach. Royal S. Series help double stalemate in 3.
(b) h3 to g1.
In Remanantes Schach, non-moving ghosts of pieces are left behind after each move to guard and block squares, I believe. A humorous twin!. Can anybody confirm this rule? The problem was originally published with Haaner chess stipulated as well, but I cannot see why.
(I) H-J. Schiegl
Frankfurter Notizen 1970
One Way Chess
Mate in 1 (PRA)
Besides the retractor seen earlier, there is a little scope for some retro-analysis as in (I). In One-Way Chess no piece may leave a square in the same direction as it enters. How did the BK arrive at a1?
Some nice sequences to finish with. Enjoy solving! (J) is the longest 2-piece problem I've found on an orthodox board. The Edge Chess condition means all moves are confined to the edge cells. Mars Circe (see pp.139–140) implies wK may not enter d8 or f8 nor bK d1 or f1.
(J) Z. Oliva
Helpstalemate in 17
Mars Circe. Edge Chess
(K) S. Emmerson original
Circe. Helpmate in 8.
White must check.
(L) Erich Bartel
Seriesmate in 13
Circe. Relegation Chess.
In Relegation Chess pieces returning to the second rank of their side turn back to pawns.