Skip to content
Tong Shu Calendar Reference

Auspicious Business Opening Dates for April 2027開業 · April 2027

By Master Sean Chan · Updated

This month carries Qing Ming (清明) — month flips to 辰 on April 5 (Singapore time): the BaZi calendar's sectional boundary for the month. Below is the universal Chinese metaphysics ranking of every day in April 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

30
days in April
25
pass hard requirements
4
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12027-04-30壬午滿 Filling奎子 (Rat)上吉
22027-04-20壬申定 Stabilising心寅 (Tiger)上吉
32027-04-05丁巳除 Removing昴亥 (Pig)上吉
42027-04-14丙寅開 Opening翼申 (Monkey)上吉
52027-04-09辛酉執 Holding井卯 (Rabbit)吉

All days in April 2027

DateDay PillarOfficerMansion ClashNotable factorsClass
2027-04-01癸丑開壁未 GoatFailed requirement: not_year_break大凶
2027-04-02甲寅閉奎申 Monkey月德 · 建除 閉 · 黃道平
2027-04-03乙卯建婁酉 Rooster黃道吉
2027-04-04丙辰除胃戌 Dog—平
2027-04-05丁巳除昴亥 Pig天德合 · 月德合 · 黃道上吉
2027-04-06戊午滿畢子 Rat建除 滿吉
2027-04-07己未平觜丑 Ox建除 平平
2027-04-08庚申定參寅 Tiger宿 參 · 黃道吉
2027-04-09辛酉執井卯 Rabbit建除 執 · 宿 井 · 黃道吉
2027-04-10壬戌破鬼辰 DragonFailed requirement: not_month_break大凶
2027-04-11癸亥危柳巳 Snake建除 危 · 黃道平
2027-04-12甲子成星午 Horse建除 成吉
2027-04-13乙丑收張未 GoatFailed requirement: not_year_break大凶
2027-04-14丙寅開翼申 Monkey建除 開 · 黃道上吉
2027-04-15丁卯閉軫酉 Rooster天德合 · 月德合 · 建除 閉吉
2027-04-16戊辰建角戌 Dog黃道吉
2027-04-17己巳除亢亥 Pig宿 亢 · 黃道平
2027-04-18庚午滿氐子 Rat建除 滿 · 宿 氐吉
2027-04-19辛未平房丑 Ox建除 平平
2027-04-20壬申定心寅 Tiger天德 · 月德 · 黃道上吉
2027-04-21癸酉執尾卯 Rabbit建除 執 · 黃道吉
2027-04-22甲戌破箕辰 DragonFailed requirement: not_month_break大凶
2027-04-23乙亥危斗巳 Snake建除 危 · 宿 斗 · 黃道平
2027-04-24丙子成牛午 Horse建除 成吉
2027-04-25丁丑收女未 GoatFailed requirement: not_year_break大凶
2027-04-26戊寅開虛申 Monkey建除 開 · 宿 虛 · 黃道吉
2027-04-27己卯閉危酉 Rooster建除 閉 · 宿 危大凶
2027-04-28庚辰建室戌 Dog黃道吉
2027-04-29辛巳除壁亥 Pig黃道吉
2027-04-30壬午滿奎子 Rat天德 · 月德 · 建除 滿上吉
Personalised next step

BaZi-Aligned Date Report — April 2027

USD 388

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

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.