Saju is the Korean four-pillars astrology system. Given a birth date + time, it produces a 4x2 grid: year/month/day/hour x heavenly stem/earthly branch. The Day Pillar (one of 60 combinations) is the personality archetype - like a 60-fold zodiac.

I built a free, no-signup calculator: https://tarofortune.pythonanywhere.com/ (Korean) / https://tarofortune.pythonanywhere.com/en (English).

What it does:

• Computes the four pillars from any birth date / time
• 60 day-pillar interpretations in both Korean and English
• Five elements (오행) balance with strength/weakness analysis
• Ten Gods (십신) relational roles
• Twelve Life Stages (십이운성) life-cycle energy
• Today is luck check based on current day pillar
• Two-person compatibility

Stack: Flask + Pillow for dynamic OG card generation. Calculator uses Meeus astronomical algorithms because solar terms (jeolgi) shift month-pillar boundaries - a calendar-day approach gets it wrong about 12 times a year.

No database. No accounts. No email collection. Just numbers in, interpretation out.

Source closed for now; happy to discuss the algorithm if anyone is curious.