Ohama Kagetaka was a seafaring pirate and served on behalf of several daimyō in and around the Seto Inland Sea during the Sengoku and Azuchi-Momoyama periods.  Kagetaka lived from 1540 to 9/7 of 1597.  Kagetaka’s origins were from Shima Province and, later, he served Takeda Shingen and Tokugawa Ieyasu as an admiral.  He had a son named Ohama Mitsutaka.  Kagetaka was also known as Minbu-saemon and Ise-no-kami.

The Ohama Group was originally based in the village of Ohama in the Tōshi District.  Kagetaka was the head of a band of pirates having influence in the Ise Bay.  The pirates were affiliated with the Kitabatake family who served as the provincial governors of Ise.  Kagetaka owned a large warship known as an atakebune.  While managing the band of pirates, he lost to Kuki Yoshitaka, a naval commander who aimed to control Shima Province through the support of Oda Nobunaga.  As a result, Kagetaka was driven out of Ise Bay.

In 1571, Kagetaka received an invitation from Tsuchiya Sadatsuna, a retainer of Takeda Shingen (the sengoku daimyō of Kai Province), to build a navy for the Takeda clan, after which he served as a retainer of the Takeda.  He became an admiral with a fleet comprised of one atakebune and fifteen smaller vessels.  After the demise of Shingen, Kagetaka served under Takeda Katsuyori. 

After the collapse of the Takeda clan in the third month of 1582, Kagetaka then served as an admiral for Tokugawa Ieyasu and was awarded a fief of 1,500 koku in Suruga Province.  Thereafter, together with Mukai Masatsuna and Mamiya Takanori, he served under the command of Honda Shigetsugu in sea and land operations.  In particular, at the Battle of Komaki-Nagakute from the third to the eleventh months of 1584, he caused trouble at sea for the forces of Hashiba Hideyoshi.  In 1590, after the transfer of Ieyasu to the Kantō, Kagetaka was further awarded 3,000 koku in Sagami and Kazusa provinces.  He was stationed in the village of Misaki in the Miura District of Sagami Province at the entrance to Edo Bay.  Kagetaka became the chief of the Misaki Group of Four.  The Ohama, along with the Mukai, the Mamiya, and the Chika clans, wielded power in this locale.  Mukai Masatsuna received an allotment of 2,000 koku.  Drawing from the smaller size of his fief, Masatsuna would have recognized Kagetaka as the chief of the Misaki Group of Four.  Nevertheless, Kagetaka was the first of the Misaki Group of Four to die.

The residence of Kagetaka in Misaki was located on the remains of the residence of Nanjō Masaharu, the former lord of Misaki Castle and a retainer of Hōjō Ujichika.  Kagetaka died in 1597 at the age of fifty-eight.  In the ninth month of 1600, his son, Mitsutaka, participated in the Battle of Sekigahara.