Anoldstorygoesthatoncetherewerefoursinglemen,leadingveryboringlives.Noneofthemweremarried,orhadlovers,ordidanythingexciting.TheyjustsataroundalldayandplayedMahjong.
OnedaytheyplayedMahjongfrom11inthemorninguntil11atnight.Duringthegame,nomatterwhowon,thewinningcardwasalwaysthe'fourcolumns'card(thecardshowsfourindependent,parallelcolumnsintwolines).Evenmoreofacoincidence,itwasNov11,or11/11.Inordertocommemoratetheday,theynicknamedit"SinglesDay".