Ten parts of a sidereal sign
Dashamsha divides each 30° rāśi into ten equal 3° parts. In the forward Parāśari rule, an odd sign starts counting with itself; an even sign starts with its ninth sign, counting the natal sign as one. Each successive 3° part moves one sign forward. At exactly 3°, 6°, or another multiple of 3°, the next part begins.
For example, 10° Gemini is in the fourth part and maps to Virgo. At 19° Scorpio, the seventh part maps to Capricorn because the sequence starts with Cancer, the ninth sign counted from Scorpio. The displayed degree within D10 stretches a 3° interval to 30°; it is a derived coordinate.
The tool calculates this site's D1 positions with Astronomy Engine 2.1.19 and an approximate Lahiri ayanamsha, then applies the sign rule. It includes seven classical grahas and mean Rahu and Ketu. The D10 Lagna comes from the transformed D1 ascendant and requires a recorded time, place, and historical UTC offset.
Keep D1 beside D10
The output keeps every D1 sign and degree beside its derived D10 placement. It shows which of the ten 3° parts contains each point. The South Indian diagram fixes the signs in place and marks the transformed Lagna. For the traditional wording, examples, and reasons other sites may differ, read the Dashamsha method guide.