Otsuka enjoyed a distinguished career as a graduate of the National Defense Academy. He joined the Maritime Self-Defense Force in 1983 and served as president of the MSDF Command and Staff College. He went on to be the director of the Defense Ministry's Intelligence Headquarters and retired last year.
Otsuka is the first former SDF member to be appointed as an ambassador. The SDF base in Djibouti was set up in 2011 and the 170 members stationed there – including an air squadron - are largely occupied with anti-piracy operations off Somalia.
The SDF members conduct warning and surveillance activities using P-3C patrol aircraft, mainly in the Gulf of Aden.
"I am determined to do my best, given my 40 years of experience in the military service, for the sake of the Japanese diplomacy," Otsuka said in an interview with NHK.
Otsuka's background suits his new role supporting one of the pillars of the Suga administration's diplomatic policy: promoting a "free and open Indo-Pacific." Its aim is to establish a rule-based international order, including the rule of law and freedom of navigation. That is largely a response to China's increasing activities in the seas around the region.
One reason for Djibouti's geopolitical significance is its location on the narrow straight that connects the Red Sea and the Gulf of Aden, a key shipping route. Major global powers consider it a gateway to Africa.
In 2017, China chose Djibouti for its first overseas military base. While Japan pushes a "free and open Indo-Pacific," China is promoting its "Belt and Road" initiative, a grand plan for an economic zone that would connect China, Africa and Europe.
One of the challenges facing Japan's new ambassador will be how to coordinate relations with China. "China has contributed to the counter-piracy operations in the Gulf of Aden. And therefore, I'm very much looking forward to finding out what we can do together," says Otsuka.
Japan is now expanding SDF operations overseas beyond anti-piracy missions. Since January, SDF units have been gathering intelligence to safeguard commercial shipping during a tense period in the Middle East.
Otsuka believes that kind of work will become increasingly important. "Japan's security is closely linked to global peace and stability. And that's why Japan has deployed forces to Djibouti, 7000 nautical miles away from Japan," he says. "Whether Japan deploys more forces overseas depends on the balance between national defense and the contribution to global peace and stability."