Day Master means the day’s Heavenly Stem
The Day Master is the upper character of the day pillar, called ilgan (일간, 日干) in Korean terminology. It is one of the ten Heavenly Stems and therefore carries a Five Phase and yin-yang association.
It should not be confused with the whole day pillar, or ilju. The Day Master is one character; the day pillar includes both its Stem and Branch.
Why everything is compared with it
A chart’s other Stems and Branches are classified by how their phases relate to the Day Master: the same phase, produced by it, controlled by it, controlling it, or producing it. Polarity adds a second distinction.
This reference system creates the Ten Gods. It gives the reader a consistent way to discuss resources, expression, peers, responsibility, and material concerns symbolically.
Strong and weak are technical, not moral
Readers assess whether the Day Master receives seasonal support, roots, and assistance or faces strong draining and controlling influences. Strong does not mean a better person, and weak does not mean a worse future.
The practical question is balance: what helps this particular chart use its qualities constructively? One character alone cannot deliver a responsible Saju reading.
Sources & further reading
Lucia’s guide is written in original language from the reference material below. Interpretive traditions vary by school and practitioner.