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Tong Shu Calendar Reference

Auspicious Business Opening Dates for October 2027開業 · October 2027

By Master Sean Chan · Updated

This month carries Han Lu (寒露) — month flips to 戌 on October 8 (Singapore time): the BaZi calendar's sectional boundary for the month. Below is the universal Chinese metaphysics ranking of every day in October 2027 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

31
days in October
27
pass hard requirements
8
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12027-10-21丙子滿 Filling參午 (Horse)上吉
22027-10-11丙寅定 Stabilising虛申 (Monkey)上吉
32027-10-31丙戌建 Establishing氐辰 (Dragon)上吉
42027-10-16辛未收 Gathering婁丑 (Ox)上吉
52027-10-04己未開 Opening房丑 (Ox)上吉

All days in October 2027

DateDay PillarOfficerMansion ClashNotable factorsClass
2027-10-01丙辰危角戌 Dog建除 危平
2027-10-02丁巳成亢亥 Pig建除 成 · 宿 亢吉
2027-10-03戊午收氐子 Rat宿 氐 · 黃道平
2027-10-04己未開房丑 Ox建除 開 · 黃道上吉
2027-10-05庚申閉心寅 Tiger月德 · 建除 閉平
2027-10-06辛酉建尾卯 Rabbit黃道吉
2027-10-07壬戌除箕辰 Dragon宿 箕吉
2027-10-08癸亥除斗巳 Snake宿 斗 · 黃道吉
2027-10-09甲子滿牛午 Horse建除 滿吉
2027-10-10乙丑平女未 GoatFailed requirement: not_year_break大凶
2027-10-11丙寅定虛申 Monkey天德 · 月德 · 宿 虛上吉
2027-10-12丁卯執危酉 Rooster建除 執 · 宿 危平
2027-10-13戊辰破室戌 DogFailed requirement: not_month_break大凶
2027-10-14己巳危壁亥 Pig建除 危 · 黃道平
2027-10-15庚午成奎子 Rat建除 成吉
2027-10-16辛未收婁丑 Ox天德合 · 月德合上吉
2027-10-17壬申開胃寅 Tiger建除 開 · 黃道上吉
2027-10-18癸酉閉昴卯 Rabbit建除 閉 · 黃道凶
2027-10-19甲戌建畢辰 Dragon—平
2027-10-20乙亥除觜巳 Snake黃道吉
2027-10-21丙子滿參午 Horse天德 · 月德 · 建除 滿上吉
2027-10-22丁丑平井未 GoatFailed requirement: not_year_break大凶
2027-10-23戊寅定鬼申 Monkey黃道吉
2027-10-24己卯執柳酉 Rooster建除 執吉
2027-10-25庚辰破星戌 DogFailed requirement: not_month_break大凶
2027-10-26辛巳危張亥 Pig天德合 · 月德合 · 建除 危上吉
2027-10-27壬午成翼子 Rat建除 成吉
2027-10-28癸未收軫丑 Ox宿 軫吉
2027-10-29甲申開角寅 Tiger建除 開 · 黃道上吉
2027-10-30乙酉閉亢卯 Rabbit建除 閉 · 宿 亢 · 黃道凶
2027-10-31丙戌建氐辰 Dragon天德 · 月德 · 宿 氐上吉
Personalised next step

BaZi-Aligned Date Report — October 2027

USD 388

A personalised PDF that re-ranks every business opening-suitable day in October 2027 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

Pillars use the 60 Jiazi day cycle anchored to the published Tong Shu. The BaZi year flips at Li Chun, the BaZi month flips at each sectional solar term — both computed from VSOP87 ephemeris data. The Twelve Officers (建除) and the 28 Mansions each have their own deterministic rotation against an authoritative anchor.

Weights come from the Dong Gong (董公擇日) school. Auspicious 神煞 add, taboo 神煞 subtract, the officer and mansion adjust, Yellow Dao adds a small bonus on top. Sum, clamp to 0–100, classify. No app shortcuts.