What is tang-changan?

Tang Chang'an is an interactive historical simulation of the Tang Dynasty capital city, built as a pure browser web app using Three.js and plain JavaScript with no build step required. The README is written in Chinese and covers version 11 of the project. The simulation models a 120x160 unit map of the city including the three grand palace halls of Daming Palace, the seven-story Wild Goose Pagoda, the Qujiang lake area, the east and west markets, farms with water irrigation, and the southern Zhuque gate. The scene runs a live day and night cycle, a four-season cycle, and a curfew system. Weather changes between rain, sandstorm, and fog, with lightning and thunder during rain. Over 200 NPCs populate the streets and speak market gossip tied to their roles (soldiers, merchants, scholars, monks, farmers, foreign traders). A historical events timeline is also woven into the experience. Players can enter the scene in an RPG mode, choosing one of four character classes: scholar, merchant, court lady, or soldier. Each class starts with a different set of currency and items. The game includes an economy with four currency types (copper coins, silk, gold ingots, and a fame score) and five types of shops where you can buy food, calligraphy supplies, clothing, collectibles, and travel passes. A stamina and charm system responds to eating and drinking. Four mini-games are available: rock-paper-scissors with NPCs, Tang Dynasty riddles, a poetry word game (picking lines that contain a given character), and couplet matching. Winning earns items from prize pools, losing gives comic consolation responses. Five palace halls can be entered in first-person view, where you walk through gallery-style exhibitions of Tang court life with captioned artwork panels. Pressing V switches between third-person and first-person camera at any time. To run the project locally, you start a simple Python web server in the project folder and open the local address in a browser. Direct file opening does not work because the project uses ES modules.