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日主 · the day stem as reference point

Day Master Calculator: Your Bazi Day Stem from a Birth Date

Today’s example at 13 Oct 2026, 14:22 CST (UTC+8) is a 庚申 Yang Metal Monkey day: the Day Master is Geng 庚 (Yang Metal). At 23:00, this calculator advances the day and shows the midnight alternative.

A scholar's relationship chart with a central Day Master tablet and ten paired medallions
日主One stem becomes the reference for nine visible stem comparisons.

Birth moment → day stem

Find the chart's reference stem

The date is required. Time is optional except near 23:00, where the late-Rat and civil-midnight day conventions can disagree.

Needed to test the 23:00 day edge.

19 February 1901–8 February 2100 · birth data is not saved

Worked example · today, not your birth chart

Geng 庚: Yang Metal Day Master

庚申 Yang Metal Monkey is the day pillar; its first character, 庚, is the Day Master.

Geng’s traditional Metal is strong and responsive to shaping. The Day Master image can describe resolve, clear distinctions and a preference for meeting a problem directly. Refinement matters as much as force: the interpretive question is how determination becomes purposeful action. Fire and Water give the classical discussion different ways of describing that shaping and expression.

Read Geng’s complete meaning and relationships →

Ten possible reference stems

Every Day Master already has a full record

Each stem record contains its six cycle pillars, hidden-stem positions, fixed partners and complete Ten Gods comparison map.

  1. 01甲 Jia

    Yang Wood · one of ten possible day-stem reference points

    Full Jia record →
  2. 02乙 Yi

    Yin Wood · one of ten possible day-stem reference points

    Full Yi record →
  3. 03丙 Bing

    Yang Fire · one of ten possible day-stem reference points

    Full Bing record →
  4. 04丁 Ding

    Yin Fire · one of ten possible day-stem reference points

    Full Ding record →
  5. 05戊 Wu

    Yang Earth · one of ten possible day-stem reference points

    Full Wu record →
  6. 06己 Ji

    Yin Earth · one of ten possible day-stem reference points

    Full Ji record →
  7. 07庚 Geng

    Yang Metal · one of ten possible day-stem reference points

    Full Geng record →
  8. 08辛 Xin

    Yin Metal · one of ten possible day-stem reference points

    Full Xin record →
  9. 09壬 Ren

    Yang Water · one of ten possible day-stem reference points

    Full Ren record →
  10. 10癸 Gui

    Yin Water · one of ten possible day-stem reference points

    Full Gui record →