Sakai was born in Gifu City on 6 August 1909.

He attended Gifu Middle School and then the Tokorozawa Flying School as a civilian.
Graduating as a pilot, he joined the NCO Reserve in February 1928, and was posted to the 6th Rentai at Pyongyang, Korea.

He remained six months with the unit on Shandong Dispatch from May 1928 (following the move of Chiang Kai-Shek’s Army into northern China in April 1928, a Japanese infantry division was despatched there to defend the Japanese in the Shandong Peninsula; a reconnaissance chutai was also sent there for six months, then being replaced by another, which also remained for a similar period).

In 1932 he entered the Army Military Academy, following which he undertook a commander’s course at Akeno, then serving there and at Tokorozawa as an instructor.

In March 1938 he was posted to the 2nd chutai of the 2nd Daitai in northern China.

On 8 March 1938 he took part in his first aerial combat over Sian.

On 25 March he was flying as leader of the second element when he engaged I-15bis’ over Yanzhou, claiming one shot down.

On 20 April he claimed three victories over Guide.

On 20 May, 24 Ki-27s from the 2nd Daitai clashed with Chinese fighters over Lanfeng. Captain Mitsugu Sawada of the 1st chutai claimed three I-15s. A fourth I-15 was claimed by Katsumi Anma in his first combat when he was flying as the third pilot in Sawada’s element. Sakai of the 2nd chutai claimed another victory. Totally, the 2nd Daitai claimed 12 victories over Lanfeng for no losses.

Further action followed over central and southern China, following which in August 1939 he moved to the Manchurian/Mongolian border with the 2nd chutai of the 64th Sentai, operating here from 20 August until the end of the Nomonhan Incident in mid September.

Following the death of Captain Shuichi Anzai in combat on 1 September 1939, he succeeded him as chutai commander, often flying seven sorties a day, his flight claiming more than eight victories.

Following the conclusion of the fighting here, he was based at Dongjingcheng, training his pilots on what became termed the ‘Sakai Method’ of combat.

In July 1941 he returned to Akeno as an instructor.

He was promoted to Major in March 1943 and was posted to the Flight Test Center, where he undertook testing of Ki-61s.

When the B-29 raids commenced, he led a defensive section at the Centre, shooting down one of these bombers.

He later became Chief Test Pilot of the Ki-100, first flying this aircraft on 11 February 1945.

He remained a pilot in the Army for more than 18 years, gaining great mastery of his art.

Sakai ended the war with 3 biplane victories and a total of 9.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1938
1	25/03/38	1	I-15bis	Destroyed	Ki-10		Yanzhou	2nd Daitai
2	20/04/38	1	Enemy aircraft	Destroyed	Ki-10 (a)		Guide	2nd Daitai
3	20/04/38	1	Enemy aircraft	Destroyed	Ki-10 (a)		Guide	2nd Daitai
4	20/04/38	1	Enemy aircraft	Destroyed	Ki-10 (a)		Guide	2nd Daitai
5	20/05/38	1	Enemy aircraft	Destroyed	Ki-27		Lanfeng	2nd Daitai
9	??/??/??	1	B-29	Destroyed	Ki-61			Army Flight Test Centre

Biplane victories: 3 destroyed.
TOTAL: 9 destroyed.
(a) Probably claimed while flying a Ki-10.

Sources:
Japanese Army Air Force fighter units and their aces 1931-1945 - Ikuhiko Hata, Yasuho Izawa and Christopher Shores, 2002 Grub Street, London, ISBN 1-902304-89-6