Typhoon Maemi (pronounced [mɛ.mi]), known in the Philippines as Typhoon Pogi,[1] was the most powerful typhoon to strike South Korea since record-keeping began in the country in 1904. Maemi formed on September 4, 2003 from a disturbance in a monsoon trough in the western Pacific Ocean. It slowly intensified into Tropical Storm Maemi while moving northwestward, becoming a typhoon on September 8. That day, favorable conditions facilitated more rapid strengthening; the storm developed a well-defined eye and reached peak maximum sustained winds of 195 km/h (120 mph).[nb 1] While near peak intensity, Maemi decelerated and began turning to the north-northeast. Soon after, the eyewall passed over the Japanese island of Miyako-jima on September 10 and produced an air pressure reading of 912 mbar (26.9 inHg), the fourth-lowest recorded in the nation. Due to warm waters, Maemi was able to maintain much of its intensity before it made landfall just west of Busan, South Korea, on September 12. The typhoon became extratropical in the Sea of Japan the next day, although its remnants persisted for several days, lashing northern Japan with strong winds.