Maritime Topics On Stamps :

Admiral Yi Sun Shin and his
Turtle Ships!

Actually the turtle boats are called Kobukson. These boats are mentioned in a report from 1413 - the regency of the ruler Taejong - for the very first time. They were the Korean warships of that time. Admiral Yi Sun Shin effectively enhanced this ship type to become a powerful weapon before and during the Seven Year War between Korea and Japan (1592 - 1598).

The boats did not only look like a turtle, they also had an armored deck like this animal. The first Taejong boats used wooden plates approx. 25 cm thick. Admiral Yi Sun Shin used iron plates. The highest deck sported iron spearheads to prevent enemies from boarding. Likewise at the stern tips of spears and swords were used. They were covered up with straw mats to deceive the enemy. A dragon figurehead was mounted on the foredeck - his mouth sporting a gun barrel. Sometimes this figurehead was also used as a battering ram. The gun ports were designed in such a way that one could see from the inside to the outside but not the other way round. The rudder banks and oars were implemented at the center that the oarsmen were safe from harm even when colliding with another ship. For each oar there were four rowers aboard. In addition the oarsmen were protected by strong plates.

Further data of the turtle boat:
  • Korean, iron-armored warship
  • trunk from spruce wood (red pine) with armor plates up to 12cm thick
  • three decks plus a lower hold for cabins and supplies,
  • a tween deck for the oarsmen and
  • an upper deck for the cannons and the fighters
  • eight oars to each side
  • 1-2 masts with a lug sail.
  • one cannon each at the bow, on top, in and under the dragon head
  • on the stern platform six cannons to each side and one underneath the representative tail
  • at both sides of the ship a further 10 gun ports
  • other sources speak of all-in-all 72 gun ports
  • Length specifications differ from 70 feet waterline to 115 ft over all
  • Width data ranges from 24 to 30 ft (upper deck)
  • Crew consisted of 80 oarsmen and sailors plus 45 soldiers

Although the turtle boat was relatively heavy ship, the builders had paid attention to speed during its construction. Usually the turtle boat used sails but turned to rudders during times of combat or calm winds. The alleged 40 cannons had different calibers. There were 11.7 cm cannons, which could shoot bullets up to 2,000 feet. Smaller cannons with a range from 650 up to 1,000 ft shot fire arrows. These arrows were equipped with a bag filled with gun powder and/or were dipped into gun powder. In addition the ship had hundreds of small openings for shooting arrows and/or throwing bombs.
The turtle boat was not only the first iron-armored warship of the world, but also a well developed and successful weapon of its time.

The Korean turtle boats are forever connected with the name of admiral Yi Sun Shin (see the illustrations on the stamps to the left and below). He lived from 1545 to 1598. His birth name was probably Chung Mu, and/or Choong Moo, but throughout literature one finds his name also as Yi Sun Sin, Li Sun Shi, Lee Shun Shin or Yi Soon Shini. Today this admiral is regarded as high as the English Horatio Nelson. He anticipated the Japanese attack on Korea in 1592 and developed the turtle boat as combat machine for the defense of his country. His headquarters was established in the port of Yosu where the boats were built as well. The first boats were finished just two days before the invasion of the Japanese at Pusan. Although the Japanese had reached and occupied Seoul after only 15 days admiral Yi Sun Shin began to fight.

In May 1592 the first battle ensued in the bay of Okpo. Admiral Yi Sun Shin and his 80 turtle boats attacked a Japanese fleet of approximately 800 ships. When 26 ships of the Japanese burned they fled. Yi pursued and was able to sink several more. Other sources say admiral Yi had only 24 turtle boats in this battle. Many engagements followed. On July the 6th, 1592 the battle at Hansan Island occured. Yi used the islands as a shield for his ships and let them attack in the formation of a crane wing, which enclosed the Japanese fleet. The battle became one of his greatest victories, see stamp below to the right. They sank 71 Japanese ships only by ramming. When the Japanese fled they were able to sink an additional 48 ships. Several Japanese ships stranded because their sailors fled ashore.

During the seven years of the war admiral Yi Sun Shin always had to fight against superior Japanese numbers and nevertheless always won the battles due to his superior tactics skill. For example he sometimes let his fleet attack using the so-called 'fishnet formation', a 'V'. Thus he concentrated fire on all the Japanese ships within the 'V's and destroyed most of them. With only 180 ships Yi sailed to the Japanese base at Pusan. More than 500 Japanese ships awaited him at the port, but by clever use of fireships and tactics the Koreans were able sink approximately half of the enemy ships.

Yi Sun Shin
To defeat Korea, the Japanese had to kill admiral Yi. Thus they used a spy, who delivered a false report about a secret Japanese fleet to the Korean king. The message should lure Yi into a trap. Yi immediately noticed the fact that the reported position was a labyrinth of reefs and rocks and refused to leave, although he had received direct orders from the king to do so. When the king heard of this, he had Yi arrested and brought to Seoul in chains. Interceders at court prevented that Yi was killed but he was degraded to a simple soldier. This happened in 1597.
Meanwhile the spy contiued his work. The Korean fleet under the new commander Won Kyun, who dismissed all faithful friends of admiral Yi, sailed into the ambush and was destroyed. When the king heard of this disaster, Yi Sun Shin was redeemed and reinstated as an admiral. His first task was to reconstruct the fleet.

Admiral Yi began the construction of new turtle ships on the island of Chon Do. When his former comrades heard of his reinstatement, they signed up in crowds. After 12 ships were finished, one night combat ensued. A Japanese fleet of an alleged 133 ships was discovered off the coast and attacked with a barrage of fire. In the darkness the Japanese panicked and withdrew. On the following day they returned and encircled Yi's small fleet. But still the Koreans succeeded in sinking 30 ships and again the Japanese turned tail.
After this battle Yi continued the construction of the fleet in Hansan. He collected duties from passing merchant vessels and made his people work in the salt-extraction industry. This bought him all the missing materials such as copper for cannons. Furthermore he succeeded to built a large and well equipped base for his new fleet.

In 1598 the Chinese emperor sent his admiral Chil Lin and his fleet to the Korean west coast. Chil Lin was a flamboyant man, who would listen to no one, but admiral Yi succeeded to win his favour. He let the Chinese participate in all his own victories as winners. As a result they mutually praised each other and the Chinese agreed to help the hard-pressed Koreans.
rebuilt turtle

Admirals honour
On November the 8th, 1598 admiral Yi Sun Shin was hit by a bullet astray and died. He stood on the bow of his flagship and led the battle. Before he died he is reported to have said: "Do not tell the others that I am dead for it could impair the battle".
Admiral Yi Sun Shin was one of the greatest heroes in Korean history. He posthumously received medals and a new military medal bore his name. Several monuments and a lot of books commemorate his life, e.g. a 17m high statue in Seoul. On the stamp to the left a statue in Chinhae is depicted. On the stamp to the right there is the holy shrine Hyun Chung Sa in Onyang, right along some turtle boats. The shrine holds flags, swords, admiral personal Yi's horn, his seal and his war diary. Today this place serves as a memorial and museum. The city of Choong Moo, which is named after him, hosts another museum. It sports a reproduction of a turtle boat (see Sao Tome stamp).

Construction of turtle boats continued after the war. They were larger and bore a turtle head instead of a dragon figurehead.

This page was created with assistance of Dr. Ernst Schlunegger, Mario Rosner, Erik Matzinger, Klaus Voelcker and Erhard Jung.

© 1998 - 2004 Bjoern Moritz, all rights reserved.

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