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Ernest Bergholt's collection The Yarborough Collection The Pachabo Collection
George Coffin's collection Previous competition problems Curios

Problems Categorised by Difficulty Rating

From January 1974, all problems published in my competitions have had a Difficulty Rating (DR) from 1 (much too easy) to 8 (extremely difficult) assigned, for the purposes of my Double Dummy Master Points Scheme.  Problems with the same DR are chained together by "nexr DRn" and "previous DRn" links.  The DRs for problems that appeared before that have DRs proposed by ace solver Jean-Marc Bihl, who very kindly undertook the task after he had submitted solutions (nearly all correct) to problems #1 to #212.

DR1 problems

#77, #119, #155, #172, #187, #229, #387, #396, #409, #410, #412, #416, #434, #463, #466, EB#1, EB#2, EB#3, EB#4, EB#5, EB#6, EB#7, EB#8, EB#9, EB#12, EB#14, EB#15, EB#17, EB#18, EB#20, EB#21, EB#22, EB#25, EB#30, EB#36, EB#37, EB#41, EB#42, EB#49, EB#51, EB#52, EB#53, EB#54, EB#55, EB#56, Y#1, Y#2, Y#3, Y#5, Y#6, Y#9, Y#10, Y#16, Y#17, Y#22, Y#23, Y#24,  Y#29, Y#30, Y#32, PAC#1, PAC#2, PAC#4, PAC#5, PAC#7, PAC#8, PAC#9, PAC#10, PAC#11, PAC#12, PAC#14, PAC#17, PAC#18, PAC#20, PAC#21, PAC#22, PAC#23, PAC#24, PAC#27, PAC#30, PAC#35, PAC#37, PAC#38, CC#1, CC#2, CC#4, CC#6, CC#7, CC#10, CC#11, CC#12, CC#13, CC#14, CC#20, CC#21, CC#22, CC#23, CC#24, CC#27, CC#28, CC#32, CC#33, CC#34, CC#35, CC#36, CC#38, CC#40, CC#47, CC#48, CC#52, CC#55, CC#62, CC#68, CC#76, CC#79, CC#80, CC#81, CC#82, CC#89, CC#92, CC#98, CC#99, CC#109, CC#110, CC#111, CC#117, CC#137, CC#140, CC#142, CC#157, CC#159, CC#161, CC#162, CC#163, CC#164, CC#165, CC#169, CC#182, CC#183, CC#184, CC#186, CC#191, CC#193, CC#194, CC#195, CC#196, CC#202, CC#203, CC#204, CC#205, CC#206, CC#207, CC#208, CC#209, CC#210, CC#212, CC#213, CC#216, CC#217, CC#218, CC#221, CC#229, CC#233, CC#234, CC#239, CC#241, CC#242, CC#243, CC#244, CC#245, CC#246, CC#247, CC#248, CC#249, CC#254, CC#255, CC#256, CC#257, CC#258, CC#260, CC#262, CC#263, CC#268, CC#270, CC#288, CC#294, CC#303, CC#304, CP#082b, CP#097b, CP#112b, CP#118c, CP#137b, CP#145b.

DR2 problems

#6, #12, #35, #40, #68, #72, #84, #87, #110, #121, #154, #174, #178, #197, #198, #204, #206, #216, #218, #223, #273, #275, #287, #294, #297, #308, #312, #313, #314, #318, #321, #349, #373, #407, #418, #422, #425, #427, #429, #435, #437, #441, #443, #449, #453, #455, #457, #461, #465, #487, #492, EB#10, EB#11, EB#13, EB#16, EB#24, EB#26, EB#28, EB#29, EB#31, EB#32, EB#33, EB#38, EB#39, EB#40, Y#4, Y#7, Y#11, Y#12, Y#18, Y#19, Y#20, Y#21, Y#25, Y#28, PAC#3, PAC#6, PAC#13, PAC#15, PAC#16, PAC#19, PAC#26, PAC#28, PAC#29, PAC#31, PAC#34, PAC#36, CC#5, CC#8, CC#9, CC#15, CC#16, CC#17, CC#19, CC#25, CC#30, CC#37, CC#41, CC#42, CC#43, CC#45, CC#49, CC#50, CC#51, CC#56, CC#57, CC#58, CC#59, CC#60, CC#61, CC#65, CC#69, CC#71, CC#75, CC#77, CC#83, CC#84, CC#85, CC#87, CC#88, CC#90, CC#91, CC#93, CC#94, CC#95, CC#96, CC#97, CC#101, CC#105, CC#108, CC#112, CC#113, CC#114, CC#115, CC#116, CC#118, CC#124, CC#125, CC#127, CC#130, CC#131, CC#132, CC#133, CC#134, CC#135, CC#136, CC#138, CC#141, CC#154, CC#156, CC#160, CC#170, CC#171, CC#172, CC#174, CC#175, CC#176, CC#177, CC#181, CC#185, CC#187, CC#188, CC#189, CC#190, CC#192, CC#197, CC#198, CC#214, CC#222, CC#223, CC#226, CC#227, CC#230, CC#231, CC#237, CC#238, CC#250, CC#251, CC#259, CC#264, CC#267, CC#272, CC#274, CC#275, CC#281, CC#283, CC#291, CC#293, CC#295, CC#296, CP#035, CP#038, CP#062, CP#071, CP#082a, CP#083, CP#094a, CP#096a, CP#101b, CP#104b, CP#107b, CP#108b, CP#113b, CP#114b, CP#117b, CP#118b, CP#123b, CP#127b, CP#131b, CP#135b, CP#139b, CP#143b, CP#145b.

DR3 problems

#3, #13, #22, #25, #28, #34, #37, #42, #43, #57, #66, #76, #91, #92, #100, #101, #105, #107, #113, #123, #124, #131, #134, #135, #146, #161, #162, #185, #217, #219, #225, #234, #246, #257, #269, #272, #277, #278, #279, #281, #302, #304, #309, #328, #342, #343, #358, #365, #368, #379, #391, #400, #401, #404, #424, #446, #447, #451, #459, #470, #477, #478, #483, #489, #501, #511, #512, EB#19, EB#23, EB#35, EB#43, Y#13, Y#14, Y#26, Y#27, Y#31, PAC#25, PAC#33, CC#26, CC#31, CC#39, CC#44, CC#46, CC#54, CC#64, CC#70, CC#74, CC#78, CC#100, CC#103, CC#104, CC#107, CC#120, CC#122, CC#128, CC#143, CC#145, CC#158, CC#167, CC#168, CC#173, CC#178, CC#179, CC#200, CC#211, CC#215, CC#219, CC#220, CC#224, CC#225, CC#232, CC#252, CC#253, CC#261, CC#265, CC#266, CC#277, CC#278, CC#279, CC#280, CC#282, CC#284, CC#285, CC#292, CC#298, CC#300, CC#301, CC#302, CP#008, CP#009, CP#011, CP#026, CP#027, CP#030, CP#031, CP#070, CP#074, CP#093, CP#094b, CP#098a, CP#098b, CP#099b, CP#100b, CP#102b, CP#105b, CP#106b, CP#109b, CP#110b, CP#111b, CP#119b, CP#121b, CP#124a, CP#124b, CP#125b, CP#126b, CP#132b, CP#133b, CP#134b, CP#138b, CP#141b, CP#146b, CP#148a.

DR4 problems

#1, #7, #9, #14, #15, #17, #24, #30, #38, #48, #49, #51, #52, #54, #55, #58, #59, #65, #67, #73, #75, #79, #81, #83, #96, #97, #114, #117, #122, #128, #129, #130, #132, #133, #137, #139, #142, #148, #152, #165, #167, #170, #177, #183, #191, #202, #205, #214, #221, #230, #236, #237, #240, #250, #251, #253, #258, #268, #271, #282, #300, #323, #326, #331, #341, #356, #376, #377, #380, #381, #383, #384, #389, #406, #428, #442, #454, #469, #471, #472, #486, #488, #494, #506, PAC#32, CC#3, CC#18, CC#29, CC#53, CC#66, CC#67, CC#86, CC#121, CC#123, CC#126, CC#129, CC#144, CC#150, CC#153,  CC#155, CC#180, CC#228, CC#235, CC#236, CC#240, CC#271, CC#276, CC#289, CC#290, CC#299, CP#007, CP#014, CP#015, CP#016, CP#020, CP#025, CP#037, CP#040, CP#051, CP#059, CP#065, CP#067, CP#069, CP#072, CP#076, CP#079, CP#080, CP#095b, CP#096b, CP#101a, CP#103a, CP#106a, CP#108a, CP#113a, CP#114a CP#115b, CP#116b, CP#120b, CP#122b, CP#132a, CP#135a, CP#140b, CP#142b, CP#143a, CP#144b, CP#147a, CP#148b.

DR5 problems

#8, #10, #16, #18, #26, #29, #33, #39, #45, #47, #50, #56, #61, #69, #70, #71, #74, #78, #82, #88, #90, #95, #98, #99, #103, #106, #112, #116, #118, #126, #140, #141, #147, #149, #150, #156, #166, #168, #171, #175, #180, #188, #189, #190, #193, #196, #199, #200, #201, #207, #208 #212, #215, #232, #241, #244, #247, #256, #263, #267, #274, #292, #298, #305, #306, #317, #322, #327, #329, #333, #336, #337, #340, #346, #347, #350, #355, #363, #375, #390, #393, #397, #408, #415, #421, #432, #440, #444, #456, #458, #467, #474, #476, #482, #485, #497, #502, #514, EB#27, EB#44, Y#8, CC#63, CC#72, CC#73, CC#102, CC#139, CC#147, CC#287, CP#004, CP#005, CP#013, CP#017, CP#023, CP#028, CP#036, CP#045, CP#048, CP#050, CP#054, CP#061, CP#077, CP#085, CP#091, CP#092, CP#097a, CP#099a, CP#107a, CP#110a, CP#118a, CP#119a, CP#120a, CP#123a, CP#125a, CP#126a, CP#131a, CP#136b, CP#146a, CP#147b.

DR6 problems

#11, #20, #27, #44, #46, #53, #63, #64, #80, #86, #89, #93, #104, #111, #115, #125, #138, #143, #151, #157, #158, #160, #163, #176, #182, #186, #209, #210, #220, #224, #228, #235, #242, #248, #249, #252, #259, #260, #262, #291, #319, #324, #334, #352, #357, #360, #378, #388, #392, #398, #399, #411, #413, #417, #420, #426, #433, #448, #450, #460, #464, #468, #490, #499, #500, #504, #508, #515, #516, #517, EB#45, Y#15, CC#146, CC#152, CC#286, CC#297, CP#010, CP#012, CP#032, CP#034, CP#039, CP#041, CP#042, CP#053, CP#055, CP#057, CP#063, CP#066, CP#073, CP#078, CP#086, CP#087, CP#088, CP#090, CP#095a, CP#109a,  CP#111a, CP#116a, CP#121a, CP#128a, CP#128b, CP#129a, CP#130b, CP#133a, CP#134a, CP#137a, CP#138a, CP#139a, CP#141a, CP#144a.

DR7 problems

#2, #4, #19, #23, #36, #41, #60, #62, #85, #94, #108, #120, #136, #145, #169, #184, #195, #226, #231, #233, #238, #245, #254, #261, #270, #276, #283, #288, #290, #299, #307, #315, #320, #361, #371, #372, #394, #395, #403, #405, #452, #462, #473, #479, #491, #493, #496, #503, #505, #507, #509, #513, CC#148, CC#149, CC#151, CP#002, CP#003, CP#022, CP#033, CP#043, CP#052, CP#058, CP#064, CP#075, CP#081, CP#100a, CP#103b, CP#104a, CP#112a, CP#115a, CP#117a, CP#122a, CP#127a, CP#136a, CP#140a, CP#142a, CP#145a.

DR8 problems

#5, #32, #102, #127, #159, #164, #173, #181, #192, #194, #203, #211, #213, #222, #227, #239, #243, #255, #264, #265, #266, #280, #284, #285, #286, #293, #295, #301, #303, #310, #311, #316, #325, #332, #335, #338, #339, #344, #348, #351, #353, #362, #364, #366, #367, #369, #370, #374, #382, #402, #414, #423, #430, #436, #438, #475, #481, #484, #495, #498, #510, CP#001, CP#006, CP#018, CP#019, CP#021, CP#024, CP#029, CP#044, CP#046, CP#047, CP#049,  CP#056, CP#060, CP#068, CP#082, CP#084, CP#089, CP#102a, CP#105a, CP#125c, CP#129b, CP#130a, CP#130c.