▶ https://mapexp.app — no install, works right away
A map that stamps every region you've traveled to, building up your travel footprint. Records Japan's 47 prefectures & 1,897 municipalities and Korea's 16 provinces & 250 municipalities — on one map.
Based on Japan's 経県値 (Keikenchi) concept, reimagined with dual-country recording, municipality-level precision, and GPS stamping. The map uses the original Keikenchi standard color palette.
- Stamp records — Tap a region to cycle its grade: Unvisited(0) → Passed(1) → Landed(2) → Visited(3) → Stayed(4) → Lived(5). Mis-taps can be undone from a toast; long-press opens details (memos, visit log)
- Dual-country view — Show Japan and Korea on one screen with per-country stats (your traveler level follows the country you're viewing)
- Municipality level — Stamp individual municipalities in the stamping view (list or mini-map); a "Municipalities" toggle renders the whole country at municipal detail
- Place names in 3 languages — Japanese municipalities in Hangul and romaji (from official MIC readings), Korean municipalities in kanji + katakana. Map place-name language is selectable independently of the UI language
- GPS location stamp — One tap detects the region you're currently in (province + municipality) and stamps it, auto-recognizing which country you're in
- GPS-verified records can't be edited or deleted; manual records allow free past-date entry
- Gamification — Per-country traveler level, kanji seal stamp book — milestone stamps plus region-completion stamps (earned by stamping every municipality of a province, or completing a regional block like Shikoku or Jeolla; shown in indigo blue), per-region and municipal score breakdowns
- Accounts & cloud sync (optional) — Sign in with email or Google. Signed-in records auto-save to the cloud and sync across your devices, merged losslessly with any local data. Without signing in, everything stays local — accounts are opt-in
- Monthly journal (members) — Your visits are auto-organized by month; write, edit, and delete multiple journal entries per month, freely re-date them, and browse your history by month or by year
- Sharing — SNS image card (game-style Lv/EXP score, rank tier, optional place-name labels and badge row, Japan/Korea/both × regions/municipalities), per-region card with share preview, QR codes, read-only share links, JSON file exchange. Overlay a friend's map on yours in a 3-color compare view (only me / only them / both). Device-to-device code sync (no account needed)
- i18n UI & routes — Korean · English · Japanese, with per-language pages (
/ko,/ja,/en) - PWA — Home-screen install, offline map caching
- Local-first & privacy — Without signing in, all records and location data stay in your browser only. GPS coordinates are used on-device and never sent to a server. See the Privacy Policy and Terms
Next.js 16 · React 19 · TypeScript · Tailwind CSS 4 · Leaflet (react-leaflet) · Zustand · Turf.js · d3-geo · Supabase (auth & cloud sync)
npm install
npm run dev # http://localhost:3000
npm run build # production build
# Regenerate localized Japanese municipality names (public/geojson/jp-muni-names.json)
node scripts/gen-muni-names.mjs- Japan: 国土数値情報 N03 (processed by smartnews-smri/japan-topography); municipality readings from the MIC local government codes (nojimage/local-gov-code-jp)
- Korea: KOSTAT administrative boundaries (southkorea/southkorea-maps), reflecting the 2026-07 reorganization
- Base tiles: CARTO / OpenStreetMap
The 経県値Ⓡ (Keikenchi) concept originates from 都道府県市区町村 (uub.jp). 経県値 is a registered trademark of uub.jp.
- Code: MIT © 2026 yabooung
- Map data: covered by the licenses of the respective sources listed under "Data sources" (Japan MLIT KSJ terms, Korea KOSTAT / southkorea-maps, MIC codes, etc.). Check the original terms before reusing the bundled GeoJSON.
- 経県値Ⓡ is a registered trademark of uub.jp; this project makes only nominative/reference use of the concept with attribution.