Adm Yamamoto Research Paper

Operation Vengeance was the name given to the mission to kill the Commander of the Japanese Combined Fleet Admiral Isoroku Yamamoto. High ranking United States military officers in the Pacific theater had to make the hard decision to go after Adm Yamamoto. The problem that they had to face was the possibility of exposing the fact that the U.S Navy had been deciphering the Japanese Imperial Naval Codes. The first thing that they had to determine was the fact. Was this man worth going after with the information that the codes breakers had provided, and was it worth the risk to the war effort to possibly expose the U.S and British code breaking abilities.

The message that ultimately lead to this mission being carried out was intercepted and decoded on April 13, 1943 at the naval

radio station Wahiawa, Hawaii. It took the codebreakers till mid-day on the 14 to finish decoding the message. After which it was passed up to Lt Commander Layton Pearl Harbor’s fleet Intel officer. Layton then immediately brought the message to Adm Nimitz. After the two of the discussed the possibility that the Japanese would figure out that they’re naval code were being deciphered. They decided that giving credit to the coast watchers on getting the Intel for the mission would hide the fact the naval codes we broken. After debating whether or not to go ahead with the mission or not. The Mission was given approval on April 17th, 1943. Which would make this the first mission in U.S military history to be approved to specifically target an individual commander for elimination.

Once the mission was approved the first issue that arose was the immense distances involved. Do to the fact that the round trip would be almost 1,400 miles. The P-38 was selected to carry out the mission. Luckily the P-38s recently arrived in the Pacific theater prior to this mission being conducted. Even with the P-38s range. The fighters would only end up having around ten minutes in the target area to wait for Yamamoto’s aircraft before having to turn back do to fuel. The fighter squadron selected to perform this mission was the 339th which was commanded by Major John Mitchell. The mission was given around a 1000-1 success rate which commanders gave a long shot at being accomplished at best.

During the planning process the major issue that arose with the mission is the fact the P-38s didn’t have drops tanks yet in theater. Due to the planes having to fly at low altitude to avoid radar increased their fuel consumption. The man that fixed this problem with one phone call was Lieutenant Colonel Viccellio. It took less than a day for the squadron to get their tanks after the phone call was made after waiting weeks for them to arrive prior to this mission. Once the mission was given to the 339th Mitchell did all of the flight planning for the mission. He decided to split the eighteen lightings into two groups. A hunter group to go after the Betty bombers and a group to provide top cover to protect against zero fighters.

For most of the route both groups would fly at wave top level to avoid being detected by Japanese radar and also they would have to fly in completed radio silence. Only after reaching their last checkpoint would the fighter climb to their planned altitudes. Mitchell planned the hunter group would climb up to 2,000 feet and the top cover group would climb up to 10,000 feet.

On April 17th Yamamoto was dining with Lt. General Hotoshi Imamura who was the army commander in charge of the Japanese base at Rabaul. Imamura tried to convince Yamamoto that he shouldn’t go on his morale tour due to the fact that only a few months earlier he was almost himself shot down by American aircraft. Other high ranking Japanese officers also tried to convince Yamamoto not to go. Yamamoto and his chief of staff who was Vice Adm. Matome Ugaki deemed the morale tour to be too important to cancel.
On April 18th which was also the first anniversary of the Doolittle Raid on Tokyo. The P-38s from the 339th took off from Henderson field at 0710 in the morning. Of the scheduled 18 P-38s to take off for the mission 16 actually took conducted the mission. One lighting was lost on takeoff due to blowing a tire, and the other lighting had to turn back due not being able to use the fuel in his external fuel tank. Both of the lightings that were lost were both part of the hunter group. So two lighting from the top cover group had to cover down in their position in the flight.

Yamamoto’s flight that morning took off at 0610 in the morning. It consisted of two Betty bombers and six zero fighters. Their plan was for the bombers to fly at 4,500 feet and their escorts zero to fly at 6,500. The Japanese crews were told that there was no enemy aircraft in the area. So the bomber crews only took a few belts of ammo with them. The zero pilots even were feeling lax enough during the flight that they had conversations during the flight even though they were supposed to be under radio silence.

The lightings were scheduled to be at the interception point at 0935. They arrived at 0934 just a one minute ahead of their scheduled time. As the fighters continued toward Bougainville where Yamamoto’s flight was scheduled to land. The hunter group was the first ones to see the bombers as they called them out at their eleven o’clock high. At that moment all of the lightings dropped their external tanks and went after bombers and zeros. The hunter group went after the bombers. Of the four hunter aircraft only Lanphier and Baber were able to engage the bombers. One aircraft couldn’t get rid of his external tanks and had to break off from the others along with his wing man.

Once the bomber noticed the attacking aircraft, they dove to just 200 feet above the jungle. Baber engaged and shot down one of the bombers. After he broke off his attack he notice the other two lightings of their hunter group were engaging the other bomber that had managed to make it out over the water. The Betty survived their attack and after Lanphier managed to shoot down a zero he then made an attack run on the last Betty and brought it down. By now the pilots knew that they’re time in the area had run out. They needed to head back to Henderson field before the zero’s that were at Bougainville launch to intercept them. The whole engagement lasted only around two minutes. Both of the Bettys were destroyed and none of the hunter aircraft were destroyed, but all had sustained damaged. Babers aircraft alone had over one hundred billet hole in it. Of the 16 p-38s that took part on the mission 15 returned back to Henderson Field.

Once back at Henderson Field Captain Lanphier was already claiming to have been the one that brought down Yamamoto.

He made this claim over the radio on the flight back, and then as soon as he got out of his plane. Which this started the controversy between Lanphier and Barber. One that continues till this day. This controversy destroyed the friendship between the two men. The pilots of the mission claim to have shot down three bombers and six zero’s that day. Though all of the zero’s return to base according to Japanese records, and only two bombers were actually a part of the flight. So officially though Barber was given credit for two bombers and Lanphier one.

Once the Japanese sent out a search team to look for Yamamoto plane. They found it in a very thick area of the jungle and could only circle overhead. They looked for any signs of survivors, but found none. The rescue party from Bougainville finally were able to hack their way through the jungle and reach the crash site sometime the following day. The rescue party found no survivors, and they found the body of Yamamoto. The death of Yamamoto was finally passed on to the Japanese Imperial Navy Ministry on the 20th of April,

1943.

Japanese official knew that his loss would devastating to the both the military and the civilian population. They decided to withhold his loss until they could figure out a way to soften the blow to the country of his loss. They finally confirmed he was dead on May 21st a little over month after he was actually killed. After his death the Ministry needed to find a new commander. The man that they picked was actually already picked by Yamamoto to replace in case something would happen to him. Koga who was at the time the commander of the 2nd fleet would take the position of the new Commander and chief of the Combined Fleet. Though he would only hold the position for only about a year. As he too would be killed in a plane crash in the Philippines.