DEMOCRATIC PEOPLES REPUBLIC OF KOREA
At 4 A.M. local time, give or take a few minutes, on a rainy Sunday morning, 25 June 1950, artillery and mortars of the Democratic Peoples Republic of Korea (DPRK North Korea) opened fire with a massive barrage on unsuspecting military forces of the Republic of Korea (ROK South Korea) positions south of the 38th Parallel, then the dividing line between the Soviet Union-supported government of North Korea and the United States-supported government of South Korea. The barrage was followed shortly afterward with attacks across the 38th Parallel by tank-supported North Korean infantry. Thus began the 3-year, 1 month long Korean War.
North Korea was well prepared for war. South Korea was not. North Koreas army (NKPA or Inmingun) consisted of approximately 223,000 troops broken down into10 divisions plus an armored brigade plus support troops:
1st NKPA Infantry Division 20th, 22nd, and 24th Infantry Regiments
2nd NKPA Infantry Division 4th, 16th, and 17th Infantry Regiments
3rd NKPA Infantry Division 7th, 8th, and 9th Infantry Regiments
4th NKPA Infantry Division 5th, 16th, and 18th Infantry Regiments
5th NKPA Infantry Division 10th, 11th, and 12th Infantry Regiments
6th NKPA Infantry Division 13th, 14th, and 15th Infantry Regiments
7th NKPA Infantry Division 1st, 2nd, and 3rd Infantry Regiments
10th NKPA Infantry Division 25th, 27th, and 29th Infantry Regiments
13th NKPA Infantry Division 19th, 21st, and 23rd Infantry Regiments
15th NKPA Infantry Division 45th, 48th, and 50th Infantry Regiments
105th Armored Brigade 107th, 109th, and 203rd Armored Regiments plus
206th Mechanized Infantry BrigadeThe armored regiments were equipped with Soviet-made T-34 tanks. South Korea had no tanks nor much in the way of anti-tank weapons. Of the infantry divisions, the 1st through 7th Infantry Divisions were "first-line" while the 10th, 13th, and 15th Infantry Divisions were "second-line" or reserve. North Korea used its "first-line" divisions in the attack on South Korea while using the "second-line" units for internal security. Front line strength of the NKPA on 25 June 1950 was approximately 90,000 men. The NKPA was supported by a small North Korean air force and an even smaller, less effective navy.