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Tong Shu Calendar Reference

Auspicious Business Opening Dates for January 2027開業 · January 2027

By Master Sean Chan · Updated

This month carries Xiao Han (小寒) — minor cold on January 5 (Singapore time): the BaZi calendar's sectional boundary for the month. Below is the universal Chinese metaphysics ranking of every day in January 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 January
26
pass hard requirements
7
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12027-01-28庚戌收 Gathering箕辰 (Dragon)上吉
22027-01-08庚寅除 Removing奎申 (Monkey)上吉
32027-01-29辛亥開 Opening斗巳 (Snake)上吉
42027-01-17己亥開 Opening柳巳 (Snake)上吉
52027-01-15丁酉成 Completing井卯 (Rabbit)上吉

All days in January 2027

DateDay PillarOfficerMansion ClashNotable factorsClass
2027-01-01癸未危斗丑 Ox建除 危 · 宿 斗平
2027-01-02甲申成牛寅 Tiger建除 成 · 黃道吉
2027-01-03乙酉收女卯 Rabbit黃道吉
2027-01-04丙戌開虛辰 Dragon建除 開 · 宿 虛吉
2027-01-05丁亥開危巳 Snake建除 開 · 宿 危 · 黃道吉
2027-01-06戊子閉室午 HorseFailed requirement: not_year_break大凶
2027-01-07己丑建壁未 Goat—平
2027-01-08庚寅除奎申 Monkey天德 · 月德 · 黃道上吉
2027-01-09辛卯滿婁酉 Rooster建除 滿 · 黃道吉
2027-01-10壬辰平胃戌 Dog建除 平平
2027-01-11癸巳定昴亥 Pig黃道吉
2027-01-12甲午執畢子 Rat建除 執吉
2027-01-13乙未破觜丑 OxFailed requirement: not_month_break大凶
2027-01-14丙申危參寅 Tiger建除 危 · 宿 參 · 黃道平
2027-01-15丁酉成井卯 Rabbit建除 成 · 宿 井上吉
2027-01-16戊戌收鬼辰 Dragon黃道吉
2027-01-17己亥開柳巳 Snake建除 開 · 黃道上吉
2027-01-18庚子閉星午 HorseFailed requirement: not_year_break大凶
2027-01-19辛丑建張未 Goat宿 張吉
2027-01-20壬寅除翼申 Monkey黃道吉
2027-01-21癸卯滿軫酉 Rooster建除 滿 · 宿 軫 · 黃道上吉
2027-01-22甲辰平角戌 Dog建除 平平
2027-01-23乙巳定亢亥 Pig天德合 · 月德合 · 宿 亢上吉
2027-01-24丙午執氐子 Rat建除 執 · 宿 氐平
2027-01-25丁未破房丑 OxFailed requirement: not_month_break大凶
2027-01-26戊申危心寅 Tiger建除 危 · 黃道平
2027-01-27己酉成尾卯 Rabbit建除 成吉
2027-01-28庚戌收箕辰 Dragon天德 · 月德 · 宿 箕上吉
2027-01-29辛亥開斗巳 Snake建除 開 · 宿 斗 · 黃道上吉
2027-01-30壬子閉牛午 HorseFailed requirement: not_year_break大凶
2027-01-31癸丑建女未 Goat—平
Personalised next step

BaZi-Aligned Date Report — January 2027

USD 388

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

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.