D10 Dashamsha: The Career Chart
Dashamsha divides each sign into 10 parts of 3° each. D10 is the chart of profession, public reputation, and career achievement. BPHS treats it as equal in importance to D9.
In D10, look at the 10th house of D1 Lagna's Dashamsha equivalent, the 10th lord, and the Sun (karaka of career). A weak 10th in D10 or a weak Sun suggests career delays or limitations despite D1 strength.
Example: A planet at 15° in a sign. In D10: 15° / 3° = 5 divisions. Aries + 5 = Virgo. The planet lands in Virgo Dashamsha.
D7 Saptamsha: Children
Divides each sign into 7 parts of ~4.286° each. D7 addresses progeny: conception timing, children's character, number of children. The 5th house and 5th lord in D7 are key. Benefics in D7 5th promise sons; malefics suggest difficulty or daughters.
Starting sign for D7 varies by Lagna sign in D1 (see BPHS Ch. 6 for the exact table). This is a complexity classical students must master.
D12 Dwadashamsha: Parents and Ancestors
Divides each sign into 12 parts of 2.5° each. D12 governs ancestral debt, inheritance, and parents' circumstances. The 9th house of D1 in D12 shows father's wealth. The 4th shows mother's comfort. A weak 9th in D12 suggests a self-made path (father's inheritance limited); strength there indicates inherited advantage or ancestral blessing.
D4 Chaturthamsha: Property and Comforts
Divides each sign into 4 parts of 7.5° each. D4 reveals property ownership, vehicles, and material comfort. A strong Moon in D4 shows domestic happiness; weak Moon suggests restlessness or homelessness themes. Saturn strong in D4 can indicate delay in acquiring property despite wealth.
⚠️ Whole-Sign Varga Houses (Not Equal-House)
This is critical and was a real bug in this codebase (fixed in commit f20f05ed). Many astrologers mistakenly calculate varga house placement using equal-house logic (dividing the zodiac into 12 equal 30° segments from the Navamsha Lagna).
Correct method: Whole-Sign
In a varga chart (D9, D10, etc.), identify the varga Lagna sign. That sign is House 1. The next sign clockwise is House 2. And so on. A planet is placed in whichever sign it occupies. There is no cuspal calculation.
Worked Example: Equal-House Mistake
Chart: D9 Lagna is Aries, Venus at 23° Scorpio in D9
Correct (whole-sign): Scorpio is the 8th sign from Aries, so Venus is in the 8th house of D9.
Mistake (equal-house): Trying to divide Scorpio (23°) by 30° to find a cusp within House 8. This is nonsensical in varga logic.
Impact: Misreading Venus in D9 House 8 as weak (enemy place) vs. correct reading (8th house of Navamsha, challenges to marriage).
Always use whole-sign in all vargas. This aligns with classical texts and the actual structure of divisional charts.