Daily Chess Improvement: Calculation required

6 comments

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  CraigB says:

  April 16, 2013 at 3:41 am

  Let’s see where this goes.

  1… Re1+ 2. Kh2 Ng4+ seems like the obvious start. White has two choices here – Kg3 and hg. But 3. Kg3 gets mated by h4+ and Qf5#.

  3. hg and black has to make a decision, 3… hg+ or 3… R:h1+. 3… R:h1+ seems better for two reasons – one, it removes the Rh1, which otherwise prevents …Bh4+, and two, it allows the Q into the attack at f1.

  Let’s try 3… R:h1+. 4. Kh3 Bh4+ 5. Kf4 g5+ eventually gets mated by Qf5 as above, so the most stubborn defense seems to be 4. K:h1 Qf1+ 5. Kh2. The way seems clear from here.

  5… hg+ 6. Kg3 Bh4+ (finally!) 7. Kf4 g5+ 8. K:g4 Qe2+ forces white to unpin the Nd2 by Qf3, since otherwise 9. f3 Q:g2 is mate and 9. Kh3 B:f2 is mate).

  After 9. Qf3 Nf6+ 10. Kh3 B:f2+ 11. Qh5 allows black the choice of two mates.

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  Anonymous says:

  April 16, 2013 at 1:26 pm

  … Re1
  Kh2 Rh1
  Kh1 Qf1
  Kh2 Ng4
  hg hg
  Kg3 Rh3
  gh3 Qh3
  Kf4 g5
  Kg5 Qh5
  Kf4 Qg4

  That’s only 10 – maybe White can extend it another move somehow by doing something like meeting Ng4 with Kg3?

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  Harry Hariharan says:

  April 16, 2013 at 1:43 pm

  Main Line that is longest with mate in 11 black moves:-
  1. … Re1+
  2. Kh2 Ng4+!
  3. hxg4 Rxh8+
  4. Kxh1 Qf8+
  5. Kh2 hxg4+
  6. Kg3 Bh4+
  7. Kf4 g5+
  8. Kxg4 Qe2+
  9. Qf3 f5+
  10. Kh3 Bf2+
  11. Qh5 Rxh5#
  Alternative Lines (to above main line) that are shorter with mates in 4 to 9 moves:-

  If 3. Kg3…h4+ 4. Kxg4…Qf5#
  If 3. Kg3…h4+ 4. Kf3…Qf5#
  If 3. Kg3…h4+ 4. Kf4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf3…hxg4+ 6. Kf4…g5+ 7. Kxg4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf3…hxg4+ 6. Kxg4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf4…g5+ 6. Kf3…hxg4+ 7. Kxg4…Qf5#
  If 7. Kh2…Bxf2#
  If 7. Kxg4…Qe2+ 8. Kh3 ..Bxf2#
  If 7. Kxg4…Qe2+ 8. Kf4 ..g5+ 9. Ke4..h5#
  If 7. Kxg4…Qe2+ 8. Qf3 ..h5+ 9. Kf4 g5#
  If 7. Kxg4…Qe2+ 8. F3 ..Qxg2+ 9. Kf4 g5#
  If 8. Ke4…f4#
  If 9. f3…Qxg2#
  If 9. Kh3…Bxg7#

  Harry

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  Harry Hariharan says:

  April 16, 2013 at 1:46 pm

  Main Line that is longest with mate in 11 black moves:-
  1. … Re1+
  2. Kh2 Ng4+!
  3. hxg4 Rxh8+
  4. Kxh1 Qf8+
  5. Kh2 hxg4+
  6. Kg3 Bh4+
  7. Kf4 g5+
  8. Kxg4 Qe2+
  9. Qf3 f5+
  10. Kh3 Bf2+
  11. Qh5 Rxh5#
  Alternative Lines (to above main line) that are shorter with mates in 4 to 9 moves:-

  If 3. Kg3…h4+ 4. Kxg4…Qf5#
  If 3. Kg3…h4+ 4. Kf3…Qf5#
  If 3. Kg3…h4+ 4. Kf4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf3…hxg4+ 6. Kf4…g5+ 7. Kxg4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf3…hxg4+ 6. Kxg4…Qf5#
  If 4. Kg3…Bh4+ 5. Kf4…g5+ 6. Kf3…hxg4+ 7. Kxg4…Qf5#
  If 7. Kh2…Bxf2#
  If 7. Kxg4…Qe2+ 8. Kh3 ..Bxf2#
  If 7. Kxg4…Qe2+ 8. Kf4 ..g5+ 9. Ke4..h5#
  If 7. Kxg4…Qe2+ 8. Qf3 ..h5+ 9. Kf4 g5#
  If 7. Kxg4…Qe2+ 8. F3 ..Qxg2+ 9. Kf4 g5#
  If 8. Ke4…f4#
  If 9. f3…Qxg2#
  If 9. Kh3…Bxg7#
  Harry

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  Yancey Ward says:

  April 16, 2013 at 4:14 pm

  I don’t see how it could start any other way than Re1, and I am pretty sure Ng4 has to be the second move, but mate in a 11 is a little beyond me at the moment unless I am willing to spend the next 2 hours on this.

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  Lousanne says:

  April 16, 2013 at 6:50 pm

  1… Re1 + 2. Kh2 Ng4+ 3. hxg4
  ( 3.Kg3 h4+ 4.Kxg4 Qf5#)
  Rxh1+ 4.Kxh1
  (4.Kg3 Bh4+ 5.Kf4 g5 + 6.Kf3 hxg4 7. Kxg4 Qf5# )
  Qf1 + 5.Kh2 hxg4 + 6.Kg3 Bh4+ 7.Kf4 g5+ 8. Kxg4 ( 8. Ke4 f5#) Qe2+ 9. Qf3+ ( 9.Kh3 Bxh2# ) f5+ 10. Kh3 Bxf2+ 11. Qh5 Rxh5#