What Is Void (空亡) in BaZi?
Calculate the two void branches for each ten-day xun, see how OpenFate checks non-day pillars, and learn why Void is not an automatic loss or failure verdict.
Overview
Void is the pair of Earthly Branches left unmatched when ten Heavenly Stems are assigned across a twelve-branch cycle. OpenFate derives the pair from the natal day pillar and reports a match when one of those branches appears in the year, month, or hour pillar; the label describes a calendrical relation, not a guaranteed event.
At a glance
- Calculation pivot
- Natal day pillar
- 甲子 / 甲戌 xun
- 戌亥空 · 申酉空
- 甲申 / 甲午 xun
- 午未空 · 辰巳空
- 甲辰 / 甲寅 xun
- 寅卯空 · 子丑空
- Current scan
- Year, month, and hour branches
- OpenFate engine
- Currently calculated
Why every xun has two void branches
A xun pairs the ten stems with ten consecutive branches, leaving two of the twelve branches without a stem. The six standard pairs are: 甲子旬 void 戌亥, 甲戌旬 void 申酉, 甲申旬 void 午未, 甲午旬 void 辰巳, 甲辰旬 void 寅卯, and 甲寅旬 void 子丑.
This is a deterministic sexagenary-cycle calculation. It should be derived from a correctly calculated day pillar rather than guessed from zodiac signs, isolated stems, the Gregorian month, or the literal meaning of the word “empty.”
- Identify the day pillar’s xun before reading the two omitted branches.
- Audit a table by confirming that ten stem-branch pairings leave exactly two branches.
What OpenFate currently calculates
The current Bazi engine derives xun void from the natal day stem and branch. It then checks the year, month, and hour branches and records which non-day pillar contains one of the two void branches; it does not label the day pillar itself as a location match.
That implementation is narrower than the many historical subtypes called true void, exchanged void, cut-road void, or four great voids. Those variants should not be attributed to an OpenFate result unless a separate versioned rule is implemented and disclosed.
- Read the result as day-xun void found in a named non-day pillar.
- Do not attach unimplemented void subtypes to the engine output.
The classical source itself rejects all-bad readings
San Ming Tong Hui explains the calendrical derivation and says the relation cannot simply be declared adverse. It discusses strength, combinations, clashes, favorable or difficult symbols, and whether void weakens something useful or reduces something already troublesome.
Modern reading should therefore name the affected pillar and symbol, then compare strength, roots, interactions, and timing. “Void” alone does not tell us what is absent, how strongly it operates, or whether the practical effect is helpful, neutral, delayed, or difficult.
- Interpret a specific affected structure rather than the label in isolation.
- Preserve uncertainty when competing interactions point in different directions.
No automatic loss, infertility, isolation, or shortened life
A void match cannot prove poverty, unemployment, infertility, divorce, abandonment, mental illness, disability, death, or a failed relationship with the person associated with a pillar. Historical deterministic claims are not modern evidence.
Health, family, employment, and financial decisions require direct facts and qualified support. Use Void as a transparent calendrical marker inside a broader cultural reading, never as a diagnosis or adverse screening label.
- Do not literalize “empty” into a factual absence or medical condition.
- Never use Void to deny opportunity, care, credit, or trust.
Sources and editorial basis
- 《三命通會》 (Sanming Tonghui)卷三「論空亡」：六旬空推導、所在柱位與不可一概作凶的但書A historical compilation covering stems and branches, Ten Gods, Nayin, Shen Sha, and multiple classical pattern systems.
- OpenFate Editorial Methodology空亡不得轉譯為醫療、家庭、就業、財務或壽命事實OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.