The BDS Website

Home of the Meson Chess Problem Database and the BDS Ladder

MENU

Home My Chess Problems BDS-50 JT Glossary Downloads Ruud Beugelsdijk
Chess Problem 1995b1c301

BDS & Michael McDowell

The Problemist Supplement, 1995

8/8/4B3/2B1s3/1*3B6/1*3Rk5/8/1K*3R1b3

#2
Sentinels
PAOs b3, c1
VAO b4 

1.PAc2 (2.PAc1[+wPc2]#)

1...Bd2 2.VAa5[+wPb4#]#
1...Sd3 2.PAa3[+wPb3]#

The black king has no flights - 1...Kd3[+bPc3]? is check from the white PAO on b3 and 1...Kd2[+bPc3]? is check from the white VAO on b4. However, if White were to try checks with his Chinese Pieces, then those non-flights become flights. For example 1.VAa5[+wPb4]+? Kd2[+bPc3]! and 1.PAa3[+wPb3]? Kd3[+bPc3]!

The key carries a switchback mate threat. Black’s only defences block the ‘non-flights’, allowing the checks tried earlier to become mates. This problem started from the novel idea of a switchback threat.

HTML5 logo

Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).