Ba Zi (八字), also known as the Four Pillars of Destiny, originates from ancient China, is believed to largely determine one’s fate. It is a method that uses the Heavenly Stems and Earthly Branches to accurately record the year, month, day, and hour. It consists of eight characters: the Year Stem and Branch, the Month Stem and Branch, the Day Stem and Branch, and the Hour Stem and Branch (eight characters in total).
For further reading: https://en.wikipedia.org/wiki/Four_Pillars_of_Destiny
During the Qing Dynasty, there was a joke about a man who became a county magistrate but hardly even knew how to write. One day, he was writing the numbers one, two, three, four, five, six, seven, … When he got to the character for “seven” (七), which should curve to the right, he wrote it curving to the left instead. The guard standing beside him said, “Your Honour, you’ve written the character ‘seven’ wrong. The character for ‘seven’ should curve this way — why did you curve it the other way?” The magistrate couldn’t stand it. He threw down his brush and said, “So what if I can’t write ‘seven’ properly? My ‘eight’ (fate) is good! You’re still a guard, and I’m still an official. Don’t you dare tell me whether I write a character wrong or not!”
From Nan Huai Jin, Zhuang Zi Nan Hua
#12 七字不好八字好
八字又称生辰八字，源自古代的中国，被认为在很大程度上决定一个人的命运。它是一种利用天干和地支来准确记录年、月、日、时的方式，由“年干，年支”、“月干，月支”、“日干，日支”、“时干，时支”，共八个干支所组成（共八个字）。
延伸阅读: https://en.wikipedia.org/wiki/Four_Pillars_of_Destiny
清朝时候有一个笑话，有一个人去做县长，字都不认识，一二三四五六七，他写到七字的时候，应该向右边弯，他写成向左边弯。站在他旁边的卫兵说，大老爷，你这个七字写错了，七字是向这边弯过来，你怎么向那边弯？这个当官的县长受不了，他把笔一丢说，格老子七字写不好，八字好，你还是当兵，我还是做官，你管我写不写错字！
出自 南怀瑾《庄子喃哗》