Question: Why were there so few naval battles in the Korean War?
About the article "Korean War", section "Naval warfare".

Candidate passages:
Compared to World War II, there are relatively few feature films depicting the Korean War. 
Yi is remembered for his numerous victories fighting the Japanese during the Japanese invasions of Korea (1592–1598).
Among his twenty-three victories, the Battle of Myeongnyang and the Battle of Hansan Island are the most famous battles.
In 1592, Toyotomi Hideyoshi gave the order to invade Korea and use it as a forward base to conquer Ming China.
After the Japanese attacked Busan, Yi began his naval operations from his headquarters at Yeosu.
Despite never having commanded a naval battle in his life, he won the Battle of Okpo, Battle of Sacheon, and several others in quick succession.
His string of victories made the Japanese generals suddenly wary of the threat at sea.
Hideyoshi was fully aware of the need to control the seas during the invasion.
Having failed to hire two Portuguese galleons to help him, he increased the size of his own fleet to 1700 vessels, assuming that he could overwhelm the Joseon navy with numerical superiority.
There were numerous reasons why Yi was so successful against the Japanese fleets.
Yi had prepared for the war by checking the status of his soldiers, granaries, and supplies, replacing them when it was necessary.
As part of this preparation, Yi resurrected and built the turtle ship, which was a considerable factor in his victories.
Yi also had a great deal of information about the southern Korean coast and he planned his battles using the sea tides and narrow straits to his advantage.
Yi was a charismatic leader, and was able to maintain his soldiers' morale despite constantly being low on supplies and food, and continuous news of countless Korean losses in ground battles.
In some records, it is stated that he went as far as to personally fulfill some of his soldiers' dying wishes.
He demonstrated his loyalty to the people by treating them with respect and fighting amongst them even when endangered.
Because of this, Admiral Yi became immensely popular among his soldiers and the Korean people, who often provided him with intelligence reports at great risk to themselves.
The Joseon panokseon were structurally stronger than Japanese ships at the time.
Panokseon had stronger hulls and could carry at least 20 cannons, compared to the Japanese 1 or 2.
Japanese ship-mounted cannons were inferior to the Koreans' in both range and power.
Cannon development had been neglected by the Korean government, so Yi personally saw to it that the technology was developed.
As such, the Korean side had several different types of cannons at their disposal in battle.
Admiral Yi was an excellent naval strategist.
The Japanese navy's strongest tactic was to board enemy ships and engage in hand-to-hand combat.
The panokseon was slower than the Japanese ships so Yi had little room for error to negate the Japanese navy's most dangerous tactic.
He was able to do so in every naval engagement he commanded.
As Yi's brilliance as a strategist revealed itself throughout the war, his legend grew.
In what could be considered his greatest victory in the Battle of Myeongnyang, Yi proved victorious in the battle with 13 panokseon, while the Japanese had at least 333 ships (133 warships, at least 200 logistical support ships).
Yi also personally exercised command over his fleets, making the attack on Japanese ships coordinated and decisive.
It was largely due to Yi's complete control of the seas that the Japanese were eventually forced to retreat, keeping Joseon safe from another Japanese invasion until the end of the war. 
In 1953 the Korean Armistice Agreement ending the Korean War and establishing the Military Demarcation Line on land made no provision for the boundary between North and South in the Western Sea.
In this area a number of islands, belonging to South Korea, lay off the Ongjin Peninsula, now occupied by North Korea.
After the United Nations Command failed to reach an agreement with North Korea, the Northern Limit Line was unilaterally set by the U.S.-led United Nations military forces on August 30, 1953.
The line was originally drawn, when North Korea had no significant naval forces, as a practical operational control measure to prevent southern incursions into the north.
However, its role has since transformed to prevent North Korean ships heading south.
This line identified the northern ambit of the area patrolled by UN forces in the Yellow Sea.
It is unclear when North Korea was informed of the existence of the NLL.
Many sources suggest this was done promptly, but in a now declassified 1973 joint diplomatic cable, the U.S. Department of State and Department of Defense stated that "We are aware of no evidence that NLL has ever been officially presented to North Korea.
"In 1973, the status of the NLL was challenged by the North Korean negotiators at the 346th meeting of the Military Armistice Commission.
At that time North Korea sent its patrol ships south of the NLL approximately 43 times in October and November 1973.
In 1999, the words of negotiators were matched with more assertive actions as North Korean vessels began challenging the NLL, although there was no dispute that a few small islands close to the North Korean coastline remained within the jurisdiction of the United Nations Command since 1953.
In 1999, North Korea unilaterally asserted a maritime Military Demilitarization Line which was configured in waters to the south of the NLL.
The dissimilar maritime boundary lines became the foundation of the overlapping territorial claims of the two Koreas.
Since 1999, North Korean fishing and naval vessels have regularly ventured across the NLL.
In most cases the North Korean vessels return north of the NLL when challenged by the South Korean military; however sometimes there have been collisions between vessels and occasionally exchanges of fire have occurred.
As the waters along the NLL are rich in Blue crab, the seaborne clashes have sometimes been dubbed the "Crab Wars".
Serious naval battles have taken place between North Korean and South Korean vessels in June 1999, June 2002 and November 2009.
In March 2010 the "Cheonan", a South Korean naval vessel, was sunk by an underwater explosion near Baengnyeong Island.
In November 2010 North Korean artillery fired on Yeonpyeong Island. 
Because neither Korea had a large navy, the Korean War featured few naval battles; mostly the combatant navies served as naval artillery for their in-country armies.
A skirmish between North Korea and the UN Command occurred on 2 July 1950; the US Navy cruiser USS "Juneau", the Royal Navy cruiser HMS "Jamaica", and the frigate HMS "Black Swan" fought four North Korean torpedo boats and two mortar gunboats, and sank them.
During most of the war, the UN navies patrolled the west and east coasts of North Korea and sank supply and ammunition ships to deny the sea to North Korea.
Aside from very occasional gunfire from North Korean shore batteries, the main threat to US and UN navy ships was from magnetic mines the North Koreans employed for defensive purposes.
During the war, five U.S. Navy ships were lost (two minesweepers, two minesweeper escorts, and one ocean tug) all of them to mines, while 87 other warships suffered from slight to moderate damage from North Korean coastal artillery.
The USS "Juneau" sank ammunition ships that had been present in her previous battle.
The last sea battle of the Korean War occurred at Inchon, days before the Battle of Incheon; the ROK ship "PC 703" sank a North Korean mine layer in the Battle of Haeju Island, near Inchon.
Three other supply ships were sunk by "PC-703" two days later in the Yellow Sea.
Women in the Naval Reserve were recalled along with their male counterparts for duty during the Korean War.