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Tong Shu Calendar Reference

Auspicious Business Opening Dates for September 2028開業 · September 2028

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 2028 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
4
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12028-09-01壬辰Completing戌 (Dog)上吉
22028-09-28己未Opening丑 (Ox)上吉
32028-09-14乙巳Completing亥 (Pig)上吉
42028-09-16丁未Opening丑 (Ox)上吉
52028-09-26丁巳Completing亥 (Pig)

All days in September 2028

DateDay PillarOfficerMansion ClashNotable factorsClass
2028-09-01壬辰戌 Dog月德 · 建除 成 · 黃道上吉
2028-09-02癸巳亥 Pig天德 · 宿 亢 · 黃道
2028-09-03甲午子 Rat建除 開 · 宿 氐
2028-09-04乙未丑 Ox建除 閉 · 黃道
2028-09-05丙申寅 Tiger
2028-09-06丁酉卯 Rabbit月德合
2028-09-07戊戌辰 Dragon宿 箕
2028-09-08己亥滿巳 Snake建除 滿 · 宿 斗
2028-09-09庚子午 Horse月德 · 建除 平 · 黃道
2028-09-10辛丑未 Goat
2028-09-11壬寅申 MonkeyFailed requirement: not_year_break大凶
2028-09-12癸卯酉 RoosterFailed requirement: not_month_break大凶
2028-09-13甲辰戌 Dog建除 危
2028-09-14乙巳亥 Pig月德合 · 建除 成上吉
2028-09-15丙午子 Rat黃道
2028-09-16丁未丑 Ox建除 開 · 黃道上吉
2028-09-17戊申寅 Tiger建除 閉
2028-09-18己酉卯 Rabbit黃道
2028-09-19庚戌辰 Dragon月德
2028-09-20辛亥滿巳 Snake建除 滿
2028-09-21壬子午 Horse四離 · 建除 平 · 宿 參
2028-09-22癸丑未 Goat宿 井
2028-09-23甲寅申 MonkeyFailed requirement: not_year_break大凶
2028-09-24乙卯酉 RoosterFailed requirement: not_month_break大凶
2028-09-25丙辰戌 Dog建除 危
2028-09-26丁巳亥 Pig建除 成 · 宿 張
2028-09-27戊午子 Rat黃道
2028-09-28己未丑 Ox建除 開 · 宿 軫 · 黃道上吉
2028-09-29庚申寅 Tiger月德 · 建除 閉
2028-09-30辛酉卯 Rabbit宿 亢 · 黃道
Personalised next step

BaZi-Aligned Date Report — September 2028

USD 388

A personalised PDF that re-ranks every business opening-suitable day in September 2028 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.

Should I open the business on the same day as my company registration?

If you can — yes. Aligning the opening with the legal incorporation compounds the day’s influence on both events. If they have to be different, prioritise the opening (the customer-facing first day) over the registration date.

Methodology

Each day’s pillar is computed from the 60 Jiazi rotation anchored against the published Tong Shu, not from any single calendar app. The BaZi year flips at Li Chun (立春) and the BaZi month flips at every sectional solar term, both calculated from VSOP87 solar-longitude data so the boundaries land on the right minute. Twelve Officers and the 28 Mansions each rotate deterministically against well-known anchors.

The per-purpose weights are Dong Gong’s (董公擇日) — adjusted where modern almanacs disagree, in favour of the Hong Kong Observatory and Taiwan CWB lineage. Auspicious stars add to the score, taboo stars subtract, the day’s officer and mansion shift it further, and Yellow Dao adds a final small bonus. The final number gets capped at 100 and mapped to one of five tiers.