Each earthly branch corresponds with a season of birth.

And while each branch represents it’s own element, other elements can prosper within the season.

This also forms the basis of how hidden heavenly stems originate from earthly branches. Take note that the list of hidden stems in basic bazi analysis do have have an exact replica of stems stated in the below table.

Season of birth (四时八节) table

Season Earthly
Branch
Hidden
Stems
Element Duration
(in days)
Spring E3 H5 + Earth 5
Spring E3 H3 + Fire 10
Spring E3 H1 + Wood 15
Spring E4 H1 + Wood 15
Spring E4 H2 – Wood 15
Spring E5 H2 – Wood 7
Spring E5 H10 – Water 8
Spring E5 H5 + Earth 15
Summer E6 H5 + Earth 5
Summer E6 H7 + Metal 10
Summer E6 H4 – Fire 15
Summer E7 H6 – Earth 15
Summer E7 H4 – Fire 15
Summer E8 H4 – Fire 7
Summer E8 H2 – Wood 8
Summer E8 H6 – Earth 15
Autumn E9 H5 + Earth 5
Autumn E9 H9 + Water 10
Autumn E9 H7 + Metal 15
Autumn E10 H7 + Metal 15
Autumn E10 H8 – Metal 15
Autumn E11 H8 – Metal 7
Autumn E11 H3 + Fire 8
Autumn E11 H5 + Earth 15
Winter E12 H1 + Wood 15
Winter E12 H9 + Water 15
Winter E1 H9 + Water 30
Winter E2 H10 – Water 7
Winter E2 H8 – Metal 8
Winter E2 H6 – Earth 15

Legend of earthly branches can be found here.

The above season of birth table is often referred to in bazi analysis to get more specifics that enable deeper readings.