This classic early 20th-century definitive from Belgium features a finely engraved portrait of King Albert I, known as the “Soldier-King” for his leadership during World War I. Issued circa 1915, the stamp belongs to the Red Cross–era wartime printings distinguished by their clean typography and bold monochrome design. The 10c red denomination was widely used for domestic letter postage, making high-quality, well-centered survivors desirable to collectors. A strong thematic piece for royal portraiture, WWI-era Belgium, and early definitive study.