In December 1903, Kolchak was en route to St. Petersburg to marry his fiancée, Sophia Omirova, when, not far from Irkutsk, he received notice of the start of war with the Empire of Japan and hastily summoned his bride and her father to Siberia by telegram for a wedding, before heading directly to Port Arthur. In the early stages of the Russo-Japanese War, he served as a watch officer on the cruiser , and later commanded the destroyer Serdity. He made several night sorties to lay naval mines, one of which succeeded in sinking the Japanese cruiser . He was decorated with the Order of St. Anna 4th class for the exploit. As the blockade of the port tightened and the Siege of Port Arthur intensified, he was given command of a coastal artillery battery. He was wounded in the final battle for Port Arthur and taken as a prisoner of war to Nagasaki, where he spent four months. His poor health (rheumatism, a consequence of his polar expeditions) led to his repatriation before the end of the war. Kolchak was awarded the Golden Sword of St. George with the inscription "For Bravery" on his return to Russia.