It was named after Admiral Mineichi Koga, commander of the Imperial Japanese Combined Fleet in the Pacific Region.
Months before, Koga flew from Palau to Davao on a “Kawanishi HSK2” flying boat to establish a new base there.
He was accompanied by Admiral Shigeru Fukodome who was riding a separate flying boat.
However, they encountered a strong typhoon on their way to Davao.
Koga’s flying boat was believed to disappear following the incident while Fukodome’s flying boat floundered along the seas of Cebu and crashed along the coast of San Fernando, Naga, Cebu.
Cebuano guerillas who caught Fukodome and other survivors of the plane crash brought them to their headquarters near Mt. Manunggal.
Col. James Cushing, an American-civilian, was the commander of the Cebuano Guerillas that time.
On April 3, Cebuano fishermen Pedro Gantuangko and Rufu Wamar found the Z Plan in the debris of Admiral Fukodome’s flying boat that were floating along the coast of Perellos, Carcar.
The Z Plan was turned over to the guerillas in Cebu and was later on sent to guerillas in Negros Oriental and eventually given to the Americans aboard the USS Crevalle.
From Basay, the Z Plan was taken to Gen. Douglas MacArthur in his base in Australia.
After thorough study and translation, they were able to decipher the Z Plan and found out that the Japanese had a weak spot in Leyte.
MacArthur proceeded with the Leyte Landing and with the help of the Z Plan, the liberation forces were able to launch a counter attack against the Japanese forces and freed the Philippines from them.