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Tong Shu Calendar Reference

Auspicious Contract Signing Dates for September 2026簽約 · September 2026

By Master Sean Chan · Updated

This month carries Bai Lu (白露) — month flips to 酉 on September 7 (Singapore time): the BaZi calendar's sectional boundary for the month. Below is the universal Chinese metaphysics ranking of every day in September 2026 for signing a contract (立券 / 交易), derived from the classical Tong Shu (通書). Contracts are agreements meant to hold — the rules favour 定 (Stabilising), 成 (Completing), and 執 (Holding) officers.

Top-ranked dates this month

30
days in September
26
pass hard requirements
5
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12026-09-25乙巳成 Completing井亥 (Pig)上吉
22026-09-02壬午開 Opening翼子 (Rat)上吉
32026-09-10庚寅執 Holding箕申 (Monkey)上吉
42026-09-13癸巳成 Completing女亥 (Pig)上吉
52026-09-15乙未開 Opening危丑 (Ox)上吉

All days in September 2026

DateDay PillarOfficerMansion ClashNotable factorsClass
2026-09-01辛巳收張亥 Pig建除 收 · 宿 張 · 黃道吉
2026-09-02壬午開翼子 Rat月德 · 建除 開上吉
2026-09-03癸未閉軫丑 Ox天德 · 建除 閉 · 宿 軫吉
2026-09-04甲申建角寅 Tiger建除 建平
2026-09-05乙酉除亢卯 Rabbit建除 除 · 宿 亢平
2026-09-06丙戌滿氐辰 Dragon宿 氐 · 黃道平
2026-09-07丁亥滿房巳 Snake—吉
2026-09-08戊子平心午 HorseFailed requirement: not_year_break大凶
2026-09-09己丑定尾未 Goat建除 定吉
2026-09-10庚寅執箕申 Monkey月德 · 建除 執 · 宿 箕上吉
2026-09-11辛卯破斗酉 RoosterFailed requirement: not_month_break大凶
2026-09-12壬辰危牛戌 Dog建除 危平
2026-09-13癸巳成女亥 Pig建除 成上吉
2026-09-14甲午收虛子 Rat建除 收 · 黃道吉
2026-09-15乙未開危丑 Ox月德合 · 建除 開 · 宿 危上吉
2026-09-16丙申閉室寅 Tiger建除 閉平
2026-09-17丁酉建壁卯 Rabbit建除 建 · 宿 壁 · 黃道吉
2026-09-18戊戌除奎辰 Dragon建除 除 · 宿 奎平
2026-09-19己亥滿婁巳 Snake—吉
2026-09-20庚子平胃午 HorseFailed requirement: not_year_break大凶
2026-09-21辛丑定昴未 Goat建除 定吉
2026-09-22壬寅執畢申 Monkey四離 · 建除 執 · 黃道平
2026-09-23癸卯破觜酉 RoosterFailed requirement: not_month_break大凶
2026-09-24甲辰危參戌 Dog建除 危平
2026-09-25乙巳成井亥 Pig月德合 · 建除 成 · 宿 井上吉
2026-09-26丙午收鬼子 Rat建除 收 · 黃道吉
2026-09-27丁未開柳丑 Ox建除 開 · 黃道吉
2026-09-28戊申閉星寅 Tiger建除 閉平
2026-09-29己酉建張卯 Rabbit建除 建 · 宿 張 · 黃道吉
2026-09-30庚戌除翼辰 Dragon月德 · 建除 除吉
Personalised next step

BaZi-Aligned Date Report — September 2026

USD 388

A personalised PDF that re-ranks every contract signing-suitable day in September 2026 against your BaZi (and, for weddings/ROM, your partner’s BaZi). It surfaces:

Order the report →

See the full glossary of classical date-selection terms in the BaZi Glossary & Auxiliary Stars.

Further reading from the blog

Selected posts from Master Sean Chan's blog covering this topic and closely related ones in practice:

Frequently asked

Why isn’t my day on the list of top 5?

The top list is the universal ranking before any personal adjustment. Many couples find their best date isn’t in the top 5. Once you account for your day pillars, the right day often shifts. That’s exactly the gap the BaZi-Aligned Date Report fills.

What does 大凶 mean and can it ever be overridden?

大凶 means the day fails a hard classical requirement: 月破 (month break), 歲破 (year break), or 四離/四絕 (a quarter-day boundary). These cannot be overridden by personal alignment; they are excluded categorically. Choose another day.

Why don’t you show times here?

Hour selection is personal. The right hour depends on your day pillar and the chosen day’s element relationship to it. Publishing universal “auspicious hours” misleads readers into thinking a generic hour is safe; it isn’t. Hours are included in the personalised report.

Where do these scores come from?

The classical Tong Shu (通書) tradition: 建除十二神 (Twelve Officers), 二十八宿 (Twenty-Eight Mansions), 月德 / 天德 (monthly and yearly virtue stars), 黃黑道 (Yellow/Black Dao), and the Dong Gong (董公) per-purpose rules. We compute these directly from astronomical solar terms — no app shortcuts.

If a contract is signed on a 大凶 day, is the contract void?

Legally no — the document is binding regardless. Energetically the method holds that the agreement carries the day’s deficits (month break weakens its longevity; year break invites reversal). Choose another day if at all possible; if you can’t, the personalised report identifies the least-bad alternative.

Methodology

Day pillars derive from the standard 60 Jiazi anchor (sexagenary day cycle, anchored against the published Tong Shu). Year pillars switch on Li Chun (立春), the first solar term of the BaZi year, computed from the truncated VSOP87 series for solar longitude. Month pillars switch on each sectional solar term. The Twelve Officers are the day branch’s offset from the month branch; the Twenty-Eight Mansions cycle every 28 days against an authoritative anchor.

Per-purpose rules follow the Dong Gong (董公擇日) tradition with adjustments encoded in our open purpose_rules.yaml. Scores are additive over the day’s present 神煞, the officer/mansion preference, and the Yellow Dao bonus, then clamped to 0–100 and classified.