General concepts

Twelve Day Officers (Jian Chu)

Also known as: day officers12 day officerstwelve day officers12 day starsjian chu建除建除十二神十二建星十二值日establish dayremove dayfull daybalance daystable dayinitiate daydestruction daydanger daysuccess dayreceive dayopen dayclose dayjian daypo daycheng daykai day建日破日成日開日

The twelve Day Officers (建除十二神, Jian Chu Shi Er Shen) are a cycle of twelve labels the Chinese almanac gives to the days, from Jian, "Establish", to Bi, "Close". The officer of a day follows from the branch of the solar month and the branch of the day, and the tradition reads each officer as more or less suited to activities such as a wedding, a move or a journey.

The twelve Day Officers are among the oldest labels of the Chinese calendar. Their names already appear in the day books (日書) found in Qin-period tombs of the third century BCE, and the Han-dynasty Huainanzi lists them in the order still used today: Jian 建 (Establish), Chu 除 (Remove), Man 滿 (Full), Ping 平 (Balance), Ding 定 (Stable), Zhi 執 (Initiate), Po 破 (Destruction), Wei 危 (Danger), Cheng 成 (Success), Shou 收 (Receive), Kai 開 (Open) and Bi 閉 (Close). Because the cycle begins with Jian and Chu, the old practitioners who chose days by it were called the "Jian Chu school". The English names vary from book to book; the ones here are those common in Singapore and Malaysia.

The officer of a day is not a matter of interpretation. It is worked out from two Earthly Branches. Each solar month of the Chinese calendar has a branch: the Tiger month begins at Li Chun around 4 February, the Rabbit month at Jing Zhe around 6 March, and so on through the year. Jian falls on the day whose branch is the month's own branch, a Tiger day in the Tiger month, and the other eleven officers follow day by day. Po, Destruction, therefore always falls on the branch opposite the month's. There is one more rule. On the day a new solar month begins, the officer of the day before repeats, so that the cycle lines up with the new month. The Qing manual Xieji Bianfang Shu (《協紀辨方書》, 1739) states it briefly: "每月交節，則疊兩值日", when the month changes, two days share one officer.

What do the officers mean? The names describe a stage of a cycle, from setting something up, through fullness and completion, to closing and storing away. The almanac turns these images into lists of suitable activities. The Xieji Bianfang Shu, the reference behind most modern almanacs, names the officers in its eleventh chapter, "用事", activity by activity. For moving house it lists Cheng and Kai among the favourable days, for opening a business Man, Cheng and Kai, for contracts and trade Man, for travel Jian and Kai. For a wedding it names no favourable officer at all and lists only those to avoid. Po, Ping, Shou and Bi appear among the days to avoid for all five of these events, except Bi for contracts.

The officers are only one layer of an almanac day. A printed Tong Shu also weighs other spirits of the day, such as Tian De (天德), the three harmonies or the Robbery Sha, so a day with a favourable officer can still carry other warnings, and different almanacs end up with different lists.

The Day Officers are a cultural tradition, not a science. They show how the tradition labels a day, not what will happen on it, and nothing shows that the officer of a date changes how an event turns out.

The free Tong Shu calendar in AstroSensus calculates the officer of every day of 2027, with no AI and no account, from the solar terms worked out from the Sun's position, counted in China Standard Time (UTC+8), the time of Singapore, Malaysia and Hong Kong, and checked against published almanacs. For five events it shows only what the eleventh chapter of the Xieji Bianfang Shu says about each officer, and it says plainly that this is the tradition, not advice.