In the Daishoreki (Daishoreki calendar which shows only the order of the long and short months) of the year, 1873, (a long month (with 30 days), a short month (with 29 days)), the long months were ni (number 2)-gatsu (February), shi (number 4)-gatsu (April), roku (number 6)-gatsu (June), ku (number 9)-gatsu (September), and juichi (number 11)-gatsu (November), and a mnemonic rhyme for remembering the long months of the year was 'nishimuku samurai' (meaning a samurai facing the west with the identical pronunciation as number 2 (ni), 4 (shi), 6 (mu; number six can be expressed as 'mu' as well as 'roku'), and 9 (ku) and the last number 11 is written in kanji (Chinese characters) 十 (meaning ten) and 一 (meaning one), and when they are written vertically, the result resembles the kanji 士 (meaning samurai), which also means that ten plus one is eleven).
天保8年（1837年）の大小暦（大月〈30日〉、小月〈29日〉）は、2月、4月、6月、9月、11月が大月であり、その覚え言葉が「西向く士」であった。