Sanmei-gaku
Tenchusatsu in Sanmei-gaku: Reading the Body Star Chart and the Void Periods
Sanmei-gaku is a fortune-telling system built on the Chinese philosophy of yin-yang and the Five Elements, systematised in Japan by Takao Yoshimasa. Like BaZi, it works from the sexagenary stems and branches, but its distinguishing feature is the "Body Star Chart" — a unique diagram that maps stars onto the human body to build a picture of the person. Many people will recognise the term "Tenchusatsu" even without knowing this tradition by name.
What the Body Star Chart is
Sanmei-gaku builds a chart centred on the stem of your Day Pillar (your Day Master), placing a star at each of five positions: centre, north, south, east and west. This is the Body Star Chart.
The centre (chest) position holds your Main Star and represents your core personality. The north (head) position reflects your relationship with elders and society; the south (abdomen), your relationship with children and subordinates; and east (right hand) and west (left hand), your relationships with your partner and with colleagues or business counterparts respectively. Mapping a person's character onto parts of the body is a distinctly Sanmei-gaku way of thinking.
The meaning of the Ten Main Stars
Ten possible stars can occupy a position on the Body Star Chart: the Star of Independence, Star of Cooperation, Star of Ease, Star of Sensitivity, Star of Service, Star of Accumulation, Star of Speed, Star of Honour, Star of Exploration, and Star of Scholarship.
The Star of Independence brings a stubborn self-reliance; the Star of Cooperation, a talent for drawing people together in harmony. The Star of Ease expresses itself naturally, achieving results while enjoying the process; the Star of Sensitivity is a delicate creativity honed in solitude. The Star of Service gains wealth by giving to others; the Star of Accumulation excels at steadily saving and protecting what it has. The Star of Speed thinks while moving; the Star of Honour builds trust through pride and a sense of duty; the Star of Exploration grows by venturing into the unknown; and the Star of Scholarship organises knowledge and is suited to teaching it to others.
Understanding Tenchusatsu (the Void)
Tenchusatsu refers to the branches that are inevitably "left over" when pairing the 10 stems with the 12 branches. Because there are 10 stems and 12 branches, grouping them ten at a time always leaves two branches unpaired — and the period governed by those leftover branches is your Void.
There are six kinds of Tenchusatsu — Rat-Ox, Tiger-Rabbit, Dragon-Snake, Horse-Goat, Monkey-Rooster, and Dog-Pig — and each tests a different theme. Dog-Pig Void concerns spirituality and learning; Monkey-Rooster Void, friendships; Horse-Goat Void, relationships with elders and parents; Dragon-Snake Void, your own sense of self; Tiger-Rabbit Void, home and household; and Rat-Ox Void, ancestry and roots.
A Void period is best understood not as "bad luck" but as "a time when your foundations haven't settled yet." The conventional advice is to avoid decisions with long-term consequences — new contracts, moving house — and instead spend the time tidying up what you already have.
How this site calculates it
Your Day Pillar's stem-branch pair is found the same way as in BaZi, and your Tenchusatsu is judged from which group of ten that pillar's index number falls into — for example, anyone whose Day Pillar falls in the Jiazi group (index 0–9) carries the Dog-Pig Void.
The five stars of the Body Star Chart are placed from the relationships between your Day Master and the stems of your Year, Month and Hour Pillars (and stems derived from their branches); which side is read as east and which as west is swapped depending on gender.
Your daily score reflects whether today's branch falls within your own Void branches — a Void day is scored down, and this is stated plainly in the full reading. Your lucky direction is the opposite of your Void's associated direction.
* This article introduces the ideas behind this divination tradition and makes no claim to scientific validity. Please enjoy your reading as entertainment.