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Tong Shu Calendar Reference

Auspicious Business Opening Dates for September 2026開業 · September 2026

By Master Sean Chan · Updated

Below is the universal Chinese metaphysics ranking of every day in September 2026 for opening a business (開市), derived from the classical Tong Shu (通書). Opening is treated as a 'beginning' — the rules favour 開 (Opening) and 建 (Establishing) officers and Yellow Dao days carrying 天德 / 月德 protection.

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
12026-09-02壬午Opening子 (Rat)上吉
22026-09-25乙巳Completing亥 (Pig)上吉
32026-09-10庚寅Holding申 (Monkey)上吉
42026-09-15乙未Opening丑 (Ox)上吉
52026-09-27丁未Opening丑 (Ox)上吉

All days in September 2026

DateDay PillarOfficerMansion ClashNotable factorsClass
2026-09-01辛巳亥 Pig宿 張 · 黃道
2026-09-02壬午子 Rat月德 · 建除 開上吉
2026-09-03癸未丑 Ox天德 · 建除 閉 · 宿 軫
2026-09-04甲申寅 Tiger
2026-09-05乙酉卯 Rabbit宿 亢
2026-09-06丙戌滿辰 Dragon建除 滿 · 宿 氐 · 黃道
2026-09-07丁亥滿巳 Snake建除 滿
2026-09-08戊子午 HorseFailed requirement: not_year_break大凶
2026-09-09己丑未 Goat
2026-09-10庚寅申 Monkey月德 · 建除 執 · 宿 箕上吉
2026-09-11辛卯酉 RoosterFailed requirement: not_month_break大凶
2026-09-12壬辰戌 Dog建除 危
2026-09-13癸巳亥 Pig建除 成
2026-09-14甲午子 Rat宿 虛 · 黃道
2026-09-15乙未丑 Ox月德合 · 建除 開 · 宿 危上吉
2026-09-16丙申寅 Tiger建除 閉
2026-09-17丁酉卯 Rabbit黃道
2026-09-18戊戌辰 Dragon
2026-09-19己亥滿巳 Snake建除 滿
2026-09-20庚子午 HorseFailed requirement: not_year_break大凶
2026-09-21辛丑未 Goat
2026-09-22壬寅申 Monkey四離 · 建除 執 · 黃道
2026-09-23癸卯酉 RoosterFailed requirement: not_month_break大凶
2026-09-24甲辰戌 Dog建除 危 · 宿 參
2026-09-25乙巳亥 Pig月德合 · 建除 成 · 宿 井上吉
2026-09-26丙午子 Rat黃道
2026-09-27丁未丑 Ox建除 開 · 黃道上吉
2026-09-28戊申寅 Tiger建除 閉
2026-09-29己酉卯 Rabbit宿 張 · 黃道
2026-09-30庚戌辰 Dragon月德
Personalised next step

BaZi-Aligned Date Report — September 2026

USD 388

A personalised PDF that re-ranks every business opening-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.

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.