This is a 1923 issue from the Republic of China, denominated at $1, and featuring the Peking Central Gate (also called the Gate of Great Centrality and Perfect Uprightness). Printed in a striking red-brown and black bicolor design, it belongs to the Peking Hall of Classics definitive series, which showcased important Chinese architectural landmarks. These stamps were produced during the early Republican period, a time of great political transition following the fall of the Qing dynasty. Higher denominations such as this $1 were mainly used for heavier parcels and international mail. Its historical and architectural theme makes it highly sought after among collectors of classic China.