My grandmother walked into a Korean Saju master's dim shop every Lunar New Year.
She paid roughly $115 for 30 minutes of someone reading 8 characters from her birth chart. Then she'd come home, sit me down, and translate it: "stop chasing the wrong thing in 2026."
It wasn't horoscope nonsense.
What Korean Saju actually is
Korean Saju (사주, "four pillars") encodes about 1,500 years of pattern recognition into 4 pillars:
- Year pillar
- Month pillar
- Day pillar
- Hour pillar
Each pillar = 2 characters. 8 total. Western astrology gets 3 data points (Sun, Moon, Ascendant). Korean Saju gets 8.
That's roughly 60x the resolution.
Why I built it
70 million Koreans live outside Korea now. K-culture is everywhere — K-pop, K-drama, K-beauty, K-food.
But this specific reading? Still locked behind a 60-year-old man speaking classical hanja.
The Korean diaspora has nowhere to get this in their own language. And the global K-culture wave has nowhere to learn what it actually means.
Day 1 stack (shipped today, May 22)
- Korean credit cards LIVE (KG Inicis V2 — all 9 major issuers)
- Global PayPal (Visa/Master/Amex/JCB, USD auto-conversion)
- 9 languages from day one (KO/EN/JP/ZH/PT-BR/ES/ID/VN/HI)
- Claude-powered explanations — written so my grandmother AND a middle schooler both get it. No jargon, no mystical fog. Just clear pattern reading.
- Pricing: $1.10 Daily Pass / $7.20 Monthly / 50% OFF Annual
6 months of solo building. Today is Day 1.
What I want feedback on
- The 9-language UX — does the explanation hold up in your native language if you grew up between two cultures?
- The Claude prompt — should the tone shift more "grandmother" or more "data analyst"?
- The price point — is $1.10/day too low for a single reading, too high for casual curiosity?
Try it (no signup required for the free draw): https://sajuapp.app
If anyone here grew up between two cultures — what got lost in translation that you'd build back?
Built solo with: Next.js · Vercel · Supabase · PortOne V2 · PayPal · Claude API · Cloudflare DNS.
Follow build-in-public:
- Cheonmyeongdang on sajuapp.app
- LinkedIn: Deokhoon Hong / Founder @ KunStudio
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