Solving Contest 2009-01-25, ISC Categ2 Round2

From ISC 2009 we present the problems of the 2nd Round of the 2nd Category (easy problems, four per round) for you to practice. No Greek solver chose this category. It is always worthwhile to put your abilities to the test.

---

Problems for solving. (The solutions are at the end of this post).

	(Problem 310) A. C. White, Good Companions, 1923 Mate in 2. #2 (7 + 3)
[3R3K/8/5Q2/8/5S2/1B6/2PB4/1qbk4]

	(Problem 311) H. Ahues, Second Prize, Die Schwalbe, 1977 Mate in 2. #2 (8 + 10)
[2q2QB1/4p1R1/2p1S1r1/4pb2/2S5/B1Kp4/P3R3/rk5s]

	(Problem 312) O. Wurzburg, British Chess Magazine, 1896 Mate in 3. #3 (3 + 4)
[8/pk1B4/p7/2K1p3/8/8/4Q3/8]

	(Problem 313) S. Eberle, First Prize, problem, 1960 Helpmate in 2. h#2 (4 + 10)
[B5Rb/8/8/1r6/8/1r1p4/1Q1p2qs/1Ks2b1k]

---

The solutions of the problems
With bold writing we include the Points, 5 points for each complete solution.


(Problem 310) A. C. White, (Good Companions, 1923), #2

Tries : [1 Bxc1+? Ke1!], [1 Ba5+? / Bb4+? / Bc3+? Bd2!].

Key : 1 Qf6-a1! (5) (zz) (The wQ half-pins the black pieces and allows the functioning of the two batteries, Pawn-Bishop and Bishop-Rook).
1...Qxa1+ / Bb2+ 2 c3#
1...Qb2+ 2 Bc3#
1...Qxb3 2 Qxc1#
1...Bxd2 2 Qxb1#


(Problem 311) H. Ahues, (Second Prize, Die Schwalbe, 1977), #2

Tries : [1 Qxf5? Sf2!], [1 Sd4? Exd4+!], [1 Sd2+? / Re1+? Kxa2!], [1 Rb2+? Kc1!].
In the next tries White opens the diagonal a2-g8 by lifting Se6, aiming to protect the Pawn in a2 when the Sc4 is also relocated, but Black closes the diagonal putting various pieces on e6. See these defenses after the Key, too.
[1 Sd8? (blocks 2 Qb8) Qe6!],
[1 Sg5? (blocks 2 Rg1) Re6!],
[1 Sf4? (blocks 2 Qf1) Be6!],
[1 Sc5? (blocks 2 Qb4) e6!].

Key : 1 Sc7! (5) ( > 2 Sd2#)
1...Qe6 / Re6 / Be6 / e6 2 Qb8# / Rg1# / Qf1# / Qb4#
1...Rxa2 2 Re1#


(Problem 312) O. Wurzburg, (British Chess Magazine, 1896), #3

Tries : [1 Kd6? Kb6!], [1 Qf1? / Qf3+? / Qc4? / Qb2+? / Qe4+? / Qg2+? Kc7!], [1 Qh5? / Qxe5? A5!], [1 Qxa6+? Kxa6!].

Key : 1 Bh3! (1) ( > 2 Qg4 (1) and 3 Qc8#)
1...a5 2 Qa6+ (3) (sacrifice, for guidance of bK)
___2...Kc7, Kb8, Ka8 3 Qc8#
___2...Kxa6 3 Bc8#


(Problem 313) S. Eberle, (First Prize, problem, 1960), h#2

Key : 1 Kg1! (Changes the diagonal pin to column pin)
1...Ka1 (Changes the column pin to diagonal pin)
___2 Qg7 (the bQ moves on the pin line and pins the wQ)
___2...Qd4# (5) (the wQ moves on the pin line and gives checkmate, despite of being observed by the pinned bQ).