Day Master 日主: the one pillar that's actually you

Your day master is a heavenly stem, so it is worth knowing what the stems are when they are not being read as a personality. They are one half of the oldest naming system in continuous use anywhere: ten stems that run against twelve earthly branches, the branches being the same twelve that carry the zodiac animals. Every year, month, day, and two-hour block in the traditional calendar is named by one stem and one branch, which is where a bazi chart's eight characters come from. Four pillars, one stem and one branch each.

The pair advances together, one step on each side at a time, and that produces the fact people usually get told without the reason. Ten stems and twelve branches could in principle make 120 combinations. Only 60 of them ever occur. Because both wheels turn in step, a stem in an odd position can only ever land on a branch in an odd position, so the yang stems meet only the yang branches and the yin stems only the yin. Half the grid is unreachable, the sequence closes after 60 steps, and that is the sexagenary cycle: the reason a Chinese sixtieth birthday is the one that matters, because it is the first time your birth year's full name comes back around.

The table below is the reference version. Each stem's four relational slots are computed from the same engine that reads your chart, so what is fed by, produces, controls, and is controlled by each stem here is exactly what the calculator will apply to you.

Read a row across and you have the whole logic of a reading in one line. Take the first stem, Jia, yang Wood. Water feeds it, it produces Fire, it controls Earth, and Metal cuts it. Whether a given year is good news for a Jia day master depends entirely on which of those four columns that year's element lands in, and on whether the chart came out strong or weak, which is the arithmetic worked in the next section.

The named relationships those columns turn into, the ten gods, get their own page: fed by becomes Resource, produces becomes Output, controls becomes Wealth, and controlled by becomes Influence, each splitting in two depending on whether the polarities match. The ten gods explained takes that apart in full.

Naming your day master is the easy part. The harder, more useful question is how much support it has. That has a real answer, not a vibe. Here it is, worked on a real chart: Elon Musk, born June 28, 1971 (birth time unpublished, so this is an honest three-pillar chart, the same one already used elsewhere on this site).

Musk's day pillar is Jia Wood: a Yang Wood day master. (Birth time unpublished, so the hour pillar is honestly left out; the strength test below renormalizes to five positions instead of seven.)

The test itself comes from Wei Qianli's 1935 Qianli Minggao: does the day master get seasonal support, does it root in the branches, do other stems stand with it? We quantify that with the position weights standardized in modern popular bazi scoring, the month branch counting heaviest, at 40% of the whole chart, because season is the classical test's biggest single factor. For each position, only elements that are the day master's own element or the one that generates it count as support, and hidden stems inside each branch carry the strength shares from Zhu Zuxia's 1999 scoring lineage (a lone hidden stem counts full weight; two-stem branches split 0.7/0.3; three-stem branches split 0.6/0.3/0.1):

19.6 of 76 possible points is 25.8%, well under the 50% line, so this chart reads weak. Notice what actually did it: the single heaviest position, the month branch at 40 points, contributed nothing at all, because a Horse month's hidden stems (Fire and Earth) don't feed Wood. That is the seasonal-timing test in action: one position, correctly weighted, can outvote everything else in the chart.

From here, favorable elements follow a fixed rule from the Yuanhai Ziping: strengthen a weak day master, drain a strong one. Weak means the chart wants company and feeding, so the favorable elements are the day master's own element and whatever generates it. For a weak Wood day master, that's Wood and Water. (A strong day master would instead favor whatever drains it, spends it, or disciplines it: the opposite instinct.)

That single rule is also what makes a year's score computable. Take 2018, the year Musk has called his hardest, in his own words. Its stem-and-branch is Wu-Xu: an Earth year stem the affinity table grades at −4.8 (Earth is what weak Wood spends itself on), over a Dog branch whose hidden stems sum to −6.6, landing inside a ten-year stretch the chart already tilts against him (−9.2). Score starts every year at a baseline of 50 and adds the three swings:

50 − 9.2 decade − 4.8 year stem − 6.6 year branch = 29.4

Twenty-nine and change is the actual number the chart carries for 2018 on Musk's own life chart on this site, the lowest candle he has. Not a coincidence and not a fit after the fact: the same three numbers, added up in the open, land on the year he names himself.

This is the one rule shown in full; every weight, threshold, and formula the calculator uses is written out and versioned in the calculation methodology.

One rule is not a reading. To see all of them run over a single life start to finish, the published sample reading works one chart the whole way through, every date and marker left checkable.