Chess openings
The opening book has 3,865 lines, 150 families, and 1,306 variations. Families and variations with a measured search volume in the build notes are indexed. The rest stay on the site for study and are left out of the sitemap.
Indexed families
Amar Opening3 lines · ECO A00Amsterdam Attack1 lines · ECO A00Barnes Opening6 lines · ECO A00 to C20Clemenz Opening2 lines · ECO A00Creepy Crawly Formation1 lines · ECO A00Global Opening1 lines · ECO A00Grob Opening20 lines · ECO A00Hungarian Opening20 lines · ECO A00 to A07Kádas Opening9 lines · ECO A00Lasker Simul Special1 lines · ECO A00Mieses Opening4 lines · ECO A00Polish Opening25 lines · ECO A00 to A05Saragossa Opening1 lines · ECO A00Sodium Attack4 lines · ECO A00Van Geet Opening33 lines · ECO A00 to C31Van't Kruijs Opening5 lines · ECO A00Ware Opening7 lines · ECO A00Nimzo-Larsen Attack18 lines · ECO A01 to A06Bird Opening28 lines · ECO A02 to B21Colle System3 lines · ECO A04 to A40Modern Defense39 lines · ECO A04 to B27Zukertort Opening47 lines · ECO A04 to A41King's Indian Attack20 lines · ECO A05 to A08Réti Opening43 lines · ECO A09 to A14English Opening176 lines · ECO A10 to C20Australian Defense1 lines · ECO A40Benoni Defense66 lines · ECO A40 to A79Borg Defense5 lines · ECO A40 to B00English Defense7 lines · ECO A40Englund Gambit9 lines · ECO A40Englund Gambit Declined7 lines · ECO A40Horwitz Defense2 lines · ECO A40Kangaroo Defense2 lines · ECO A40Mikenas Defense4 lines · ECO A40Polish Defense2 lines · ECO A40Pterodactyl Defense33 lines · ECO A40 to B27Queen's Pawn Game82 lines · ECO A40 to D05Old Indian Defense14 lines · ECO A41 to A55Rat Defense11 lines · ECO A41 to C00Robatsch Defense1 lines · ECO A41Wade Defense1 lines · ECO A41Indian Defense53 lines · ECO A43 to E60Amazon Attack2 lines · ECO A45 to D00Canard Opening1 lines · ECO A45Paleface Attack1 lines · ECO A45Trompowsky Attack10 lines · ECO A45Torre Attack6 lines · ECO A46 to A48Yusupov-Rubinstein System1 lines · ECO A46East Indian Defense1 lines · ECO A48London System4 lines · ECO A48 to D02Mexican Defense2 lines · ECO A50Grünfeld Defense59 lines · ECO A56 to E60Benko Gambit8 lines · ECO A57 to A59Benko Gambit Declined6 lines · ECO A57Dutch Defense69 lines · ECO A80 to A99Barnes Defense1 lines · ECO B00Carr Defense2 lines · ECO B00Duras Gambit1 lines · ECO B00Fried Fox Defense1 lines · ECO B00Goldsmith Defense2 lines · ECO B00Hippopotamus Defense2 lines · ECO B00King's Pawn Game38 lines · ECO B00 to C44Lemming Defense1 lines · ECO B00Lion Defense6 lines · ECO B00 to B07Nimzowitsch Defense43 lines · ECO B00Owen Defense8 lines · ECO B00Pirc Defense28 lines · ECO B00 to B09St. George Defense4 lines · ECO B00Ware Defense2 lines · ECO B00Scandinavian Defense45 lines · ECO B01Alekhine Defense56 lines · ECO B02 to B05Czech Defense1 lines · ECO B07Caro-Kann Defense110 lines · ECO B10 to B19Sicilian Defense400 lines · ECO B20 to B99French Defense211 lines · ECO C00 to C19Bongcloud Attack1 lines · ECO C20Center Game18 lines · ECO C20 to C22King's Pawn Opening3 lines · ECO C20Portuguese Opening3 lines · ECO C20Center Game Accepted1 lines · ECO C21Danish Gambit1 lines · ECO C21Danish Gambit Accepted6 lines · ECO C21Danish Gambit Declined1 lines · ECO C21Bishop's Opening41 lines · ECO C23 to C43Vienna Game41 lines · ECO C25 to C29King's Gambit1 lines · ECO C30King's Gambit Declined53 lines · ECO C30 to C32King's Gambit Accepted137 lines · ECO C33 to C39Elephant Gambit4 lines · ECO C40Gunderam Defense1 lines · ECO C40King's Knight Opening3 lines · ECO C40 to C44Latvian Gambit17 lines · ECO C40 to C44Latvian Gambit Accepted9 lines · ECO C40Philidor Defense44 lines · ECO C41Petrov's Defense50 lines · ECO C42 to C43Dresden Opening1 lines · ECO C44Irish Gambit1 lines · ECO C44Ponziani Opening16 lines · ECO C44Scotch Game53 lines · ECO C44 to C45Three Knights Opening6 lines · ECO C46Four Knights Game49 lines · ECO C47 to C50Italian Game187 lines · ECO C50 to C59Ruy Lopez235 lines · ECO C60 to C99Blackmar-Diemer Gambit18 lines · ECO D00Rapport-Jobava System3 lines · ECO D01Richter-Veresov Attack8 lines · ECO D01Queen's Gambit Declined211 lines · ECO D02 to D69Rubinstein Opening6 lines · ECO D05Queen's Gambit1 lines · ECO D06Slav Defense52 lines · ECO D10 to D19Queen's Gambit Accepted63 lines · ECO D20 to D29Semi-Slav Defense72 lines · ECO D30 to D49Tarrasch Defense27 lines · ECO D32 to D34Neo-Grünfeld Defense25 lines · ECO D70 to D79Catalan Opening32 lines · ECO E00 to E09Blumenfeld Countergambit3 lines · ECO E10Bogo-Indian Defense21 lines · ECO E11Queen's Indian Defense58 lines · ECO E12 to E19Nimzo-Indian Defense104 lines · ECO E20 to E59King's Indian Defense119 lines · ECO E60 to E99
More families
Anderssen's Opening2 lines · ECO A00Formation2 lines · ECO A00Polish Opening, with d52 lines · ECO A00Valencia Opening1 lines · ECO A00Zukertort Defense2 lines · ECO A04King's Indian Attack, with Bf55 lines · ECO A07King's Indian Attack, with e62 lines · ECO A07English Orangutan2 lines · ECO A15Montevideo Defense1 lines · ECO A40Slav Indian2 lines · ECO A40 to A50Zaire Defense1 lines · ECO A40Basque Opening1 lines · ECO A45Döry Defense1 lines · ECO A46Marienbad System2 lines · ECO A47Pseudo Queen's Indian Defense2 lines · ECO A47London System, with Bd31 lines · ECO A48London System, with Be23 lines · ECO A48Queen's Indian Accelerated1 lines · ECO A50Vulture Defense1 lines · ECO A56Benko Gambit Accepted10 lines · ECO A57 to A59French Defense, Classical, 4. Bg51 lines · ECO C12Vienna Gambit, with Max Lange Defense15 lines · ECO C25Blackmar-Diemer Gambit Accepted22 lines · ECO D00Blackmar-Diemer Gambit Declined9 lines · ECO D00Rapport-Jobava System, with e61 lines · ECO D01Semi-Slav Defense Accepted1 lines · ECO D44Blumenfeld Countergambit Accepted1 lines · ECO E10Queen's Indian Defense, with e314 lines · ECO E14Queen's Indian Defense, with e3, Bb4+ Line1 lines · ECO E14Queen's Pawn, Mengarini Attack1 lines · ECO E60