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Tong Shu Calendar Reference

Auspicious Business Opening Dates for April 2026開業 · April 2026

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 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 April
24
pass hard requirements
4
rank as 上吉
5
top picks below
DateDay PillarOfficer 建除 Mansion 宿Clash 沖Class
12026-04-25壬申定 Stabilising牛寅 (Tiger)上吉
22026-04-10丁巳除 Removing井亥 (Pig)上吉
32026-04-30丁丑收 Gathering壁未 (Goat)上吉
42026-04-07甲寅開 Opening畢申 (Monkey)上吉
52026-04-14辛酉執 Holding張卯 (Rabbit)吉

All days in April 2026

DateDay PillarOfficerMansion ClashNotable factorsClass
2026-04-01戊申執室寅 Tiger建除 執吉
2026-04-02己酉破壁卯 RabbitFailed requirement: not_month_break大凶
2026-04-03庚戌危奎辰 Dragon建除 危平
2026-04-04辛亥危婁巳 Snake建除 危 · 黃道平
2026-04-05壬子成胃午 HorseFailed requirement: not_year_break大凶
2026-04-06癸丑收昴未 Goat—平
2026-04-07甲寅開畢申 Monkey建除 開 · 黃道上吉
2026-04-08乙卯閉觜酉 Rooster建除 閉凶
2026-04-09丙辰建參戌 Dog宿 參 · 黃道吉
2026-04-10丁巳除井亥 Pig天德合 · 月德合 · 宿 井上吉
2026-04-11戊午滿鬼子 Rat建除 滿吉
2026-04-12己未平柳丑 Ox建除 平平
2026-04-13庚申定星寅 Tiger黃道吉
2026-04-14辛酉執張卯 Rabbit建除 執 · 宿 張 · 黃道吉
2026-04-15壬戌破翼辰 DragonFailed requirement: not_month_break大凶
2026-04-16癸亥危軫巳 Snake建除 危 · 宿 軫 · 黃道平
2026-04-17甲子成角午 HorseFailed requirement: not_year_break大凶
2026-04-18乙丑收亢未 Goat宿 亢平
2026-04-19丙寅開氐申 Monkey建除 開 · 宿 氐 · 黃道吉
2026-04-20丁卯閉房酉 Rooster天德合 · 月德合 · 建除 閉平
2026-04-21戊辰建心戌 Dog黃道吉
2026-04-22己巳除尾亥 Pig黃道吉
2026-04-23庚午滿箕子 Rat建除 滿 · 宿 箕吉
2026-04-24辛未平斗丑 Ox建除 平 · 宿 斗平
2026-04-25壬申定牛寅 Tiger天德 · 月德 · 黃道上吉
2026-04-26癸酉執女卯 Rabbit建除 執 · 黃道吉
2026-04-27甲戌破虛辰 DragonFailed requirement: not_month_break大凶
2026-04-28乙亥危危巳 Snake建除 危 · 宿 危 · 黃道凶
2026-04-29丙子成室午 HorseFailed requirement: not_year_break大凶
2026-04-30丁丑收壁未 Goat天德合 · 月德合上吉
Personalised next step

BaZi-Aligned Date Report — April 2026

USD 388

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

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.