Manually Plot Your BaZi Once: A Reference for Verification

The term 自己手排一次八字 refers to manually deriving a Four Pillars chart once, by hand, as a deliberate exercise. It is not meant to replace software or tables. It serves to give the reader a reference point that can be checked independently. The exercise is useful because it makes visible the underlying rules that a calculator applies automatically. When one has done the work once, one is less dependent on trusting a tool and better able to recognise where a chart may have gone wrong.

手排一次的用途是建立参照

The purpose of doing one manual calculation is not to abandon tools. It is to build a reference point that you yourself can verify. A hand-calculated chart provides a fixed example against which later engine output can be compared. This matters because different tools may disagree, and without an independent reference it is difficult to tell which one is in error. The manual method forces attention to the boundaries that define each pillar: the solar term for the month, the 立春 point for the year, the day count for the day pillar, and the two-hour block for the hour. Once these are understood, a chart ceases to be a black box.

年柱：看立春

The year pillar is determined by 立春, the beginning of spring. After 立春, the new year is in force; before 立春, the previous year is still in force. This is different from both the Gregorian New Year on 1 January and the lunar New Year on the first day of the first lunar month. A date in late January or early February therefore requires special attention. For example, a person born in early February of a given calendar year may still belong to the previous 干支 year if 立春 has not yet occurred. The year boundary is not a civil or lunar festival boundary but a solar-term boundary. This is one of the first places where software output may differ from expectation if the software has been set to use lunar new year rather than 立春.

月柱：看节，查五虎遁

The month pillar is built in two parts. The earthly branch of the month is set by the solar term, or 节, that currently governs. The twelve month branches follow the sequence from 寅 for the first solar month after 立春, through 卯，辰，巳，午，未，申，酉，戌，亥，子, and 丑. The heavenly stem of the month is then derived from the year stem by the 五虎遁 formula. The formula is: 甲己之年丙作首，乙庚之岁戊为头，丙辛必定寻庚起，丁壬壬位顺行流，戊癸何方发，甲寅之上好追求. In practice this means that a 甲 or 己 year begins the first month with 丙寅; a 乙 or 庚 year begins with 戊寅; a 丙 or 辛 year begins with 庚寅; a 丁 or 壬 year begins with 壬寅; and a 戊 or 癸 year begins with 甲寅. The monthly stem is obtained by continuing the sexagenary sequence from that starting pair. The key point is that the month is not the lunar month. It is the period between two solar terms, beginning at the 节. The 中气, or mid-point, does not start a new month pillar.

日柱：只能查表

The day pillar has no mnemonic. It cannot be derived from the year, month, or hour. It must be read from a table or converted by a programme. The day pillar is simply the sexagenary index of the day in the uninterrupted sixty-day cycle. On this site, the engine obtains the day pillar by taking the Julian day number and reducing it modulo sixty. The remainder is then mapped to the corresponding 干支 pair. Because the day cycle is continuous and independent of solar terms or clock time, a small error in date handling can shift the entire day pillar. This is another reason why a hand-checked example is valuable: it lets the reader confirm whether the engine is using the correct civil date and the correct conversion. The day pillar changes at midnight in most modern conventions, although some older methods used a different boundary. The reference entry assumes the standard modern convention of the day changing at local midnight.

时柱：看钟点，查五鼠遁

The hour pillar also has two parts. The earthly branch is set by the two-hour block, or 时辰, in which the birth falls. Each branch covers two hours of clock time: 子 is roughly 23:00 to 01:00, 丑 01:00 to 03:00, 寅 03:00 to 05:00, and so on through 亥. The heavenly stem of the hour is then derived from the day stem by the 五鼠遁 formula. The formula is: 甲己还加甲，乙庚丙作初，丙辛从戊起，丁壬庚子居，戊癸何方发，壬子是真途. In practice, a 甲 or 己 day begins the 子 hour with 甲子; a 乙 or 庚 day begins with 丙子; a 丙 or 辛 day begins with 戊子; a 丁 or 壬 day begins with 庚子; and a 戊 or 癸 day begins with 壬子. The hour stem is then continued from that starting pair. The critical boundary is the start of the 子 hour, which can be treated as 23:00 in the standard modern method. Some traditions use a different handling for the period from 23:00 to midnight, but the reference entry follows the common convention in which the day changes at midnight and the 子 hour begins at 23:00.

手排之后再看工具的差别

After one manual calculation, the reader is in a different position when looking at tool output. Instead of only noticing that one tool differs from another, the reader can see which pillar is wrong. A mismatch in the year pillar will point to a 立春 handling error. A mismatch in the month pillar will point to a solar-term or 五虎遁 issue. A mismatch in the day pillar will point to a date conversion or modulo error. A mismatch in the hour pillar will point to a time boundary or 五鼠遁 issue. This diagnostic ability is the main benefit of the exercise. It changes the reader from a passive consumer of results into someone who can check the structure of a chart. The site engine is deterministic: the same input always produces the same output. That makes it suitable as a comparison against the hand-derived chart. If the hand chart and the engine disagree, the difference can be isolated to one of the four pillars rather than remaining a vague discrepancy. The whole process for a known date takes about ten minutes once the rules are understood, and the resulting reference example can be reused for later checks.