Two birthdays,
three ways of counting

What calculation rules are used?

Weton and neptu

Weton combines the seven-day week and five-day pasaran, repeating every 35 days. Weekday values: Minggu 5, Senin 4, Selasa 3, Rabu 7, Kamis 8, Jumat 6, Sabtu 9. Pasaran values: Legi 5, Pahing 9, Pon 7, Wage 4, Kliwon 8. Their sum is neptu (7–18); two people's sum is 14–36.

Three calculation methods

Research papers describe different divisors. Division by eight cycles Pegat, Ratu, Jodoh, Topo, Tinari, Padu, Sujana and Pesthi across sums 1–36. Division by seven uses wasesa segara, tunggak semi, satriya wibawa, sumur sinaba, satriya wirang, bumi kapetak and lebu katiyup angin. Division by four uses gentho, gembili, sri and punggel.

Hartono, 「Petung dalam Primbon Jawa」 Litera 15(2), 2016 (UNY) ↗

Why are the names not interpreted?

Papers give differing explanations, usually judgments of good or bad outcomes. This screen shows rule-based values and names only, so those judgments are not reproduced.

What was and was not verified

• Weekdays matched Hong Kong Observatory data for all 24,472 dates in 1960–2026. Six externally published dates anchor the five-day cycle.
• Eight matching name-value cells in two papers confirmed the neptu table, and seven worked totals in another paper supported it.
• The 1–36 table repeats every eight entries. Its examples (27 as Jodoh, 22 as Padu) were reproduced exactly.
• The original lists remainders starting at 1, so exact multiples are assigned the final name. This is our interpretation, not an explicit instruction in the original.
• The same paper mentions dividing by 10 but supplies no ten-name list, so that method is not calculated.
• We could not inspect a scan of the original Kitab Primbon Betaljemur Adammakna. We used excerpts reproduced in papers.
• The 36-point Kundli compatibility score is not calculated because five of its eight scoring tables were illegible in the original OCR.
• Methods and names vary further by region and family. These three are not an exhaustive list.