To answer some points made at various timesby varius people :-
1. Night-time navigation during early WW2 was done by:
a) Celestial Navigation
b) Dead Reckoning
c) Radio Navigation
A) Navigation by the Planets & the Stars, as used by ALL Navies at night, in conjuction with B.
B) As described by IKE99 previously. Plot a course ( degrees ) and use your charts & speed.
C) In two forms, one of which ( ADF ) was used by the Japs.
This system was in use by the US WAVES during the war and did not use anything ( A & B ) that the Japs did not have or know.
2. From :-
http://www.pacificwrecks.com/people/veterans/kudo.html
The Tainan Kokutai was renamed the 251st Kokutai in early 1943. In May of that year they received two J1N1 Gekko (Irving) nightfighters armed with upward and downward firing 20mm cannons. Flying from Lakunai Airfield near Rabaul, Kudo was the first to test the aircraft in combat, flying with Lt. (jg) Akira Sugawara as observer. He would become the first night fighter ace on either side of the Pacific War. Satoru Ono also flew from Rabaul.
June 26, 1943
Shot down two B-17s, firing from below using 164 rounds of 20mm ammunition.
July 7, 1943
Took off for an evening patrol from Ballale flying with Akira Sugawara as observer. Thie Gekko used its two downward pointing 20mm cannons (on other occasion he had used the guns that pointed upwards). This would have required Kudo to approach the Hudson unseen from above and behind and then firing when in position 30 degrees above the Hudson's fore-aft axis (allowing for deflection).
Claims in C5M Babs
1. B-17 by aerial burst bomb (August 29, 1942)
P. B-17 by aerial burst bomb (August 29, 1942)
Claims in J1N1 Gekko
P. B-24 (June 30, 1943) possibly 42-40254 307th BG, MACR 30
Confirmed Night Fighter Victories
1 . B-17E "Honi Kuu Okole" 41-9244 (May 21, 1943)
2 . B-17E 41-9011 (May 21, 1943)
3 . B-17E "Georgia Peach" 41-24454 (June 13, 1943)
4 . B-17E "Naughty But Nice" 41-2430 (June 26, 1943)
5. B-17F "Taxpayers Pride" 41-24448 (June 26, 1943)
6. B-17F "Pluto" 41-24543 (June 30, 1943)
7. RNZAF A-28 Hudson NZ2033 (July 7, 1943) observer Sugiwara
So the Japs did night fighter combat before the USA & in our time frame.
3. In Europe, the British choose to do night raids to minimise the losses on their aircraft from enemy fire, dispite the increases in OPS losses, and the lessening of the effectiveness of their bomb hits. The USA, on the other hand choose to maximise the damage caused by making daylight raids only, despite the high losses to enemy AA & aircraft. In the Pacific, the USA initially choose night raids, but when they learned that the Japs had a night fighter capacity, they switched to day raids.