Japanese Radar Of World War II

by Martin Favorite

I am frequently surprised at the number of people who believe the Japanese never developed radar during WW II. In fact some of the first radar was developed in Japan by a Dr. Yagi, hence you will find the aerials for many early radar systems referred to as a "Yagi Antennae".

The Japanese military was late to understand the value of radar, but when development was finally undertaken full force, some fairly effective sets were developed and employed during the war. Each known type of Japanese radar is discussed below, and wherever possible a photo demonstrating a type in operational deployment will be shown.

Army Radar Development And Training Groups

During the war the following radar related installations were formed by the Imperial Army :

Tama Army Technology Research Institute formed 11 June 43 for radar research

Army Radio Wave Training Unit formed 12 Feb 44 for training radar operators

Army Radio Wave Weapons Training Department revised 28 Apr 45

1st Radio Wave Guidance Unit formed 12 Jun 45

Navy Radar Development And Training Groups

The Naval Technical Department was in charge of all Navy radar development. Their main establishment would have been in Tokyo, with other facilities constructed as needed.

Development Of Radar

While the Army did have a radar development program, the Imperial Navy seems to have been the primary developer of Japanese radar. Given the losses that the Navy sustained in part because of US Navy radar, this is somewhat understandable.

Air and Surface Search Radars

Type 11

Became Operational	June 1943
War Status	used operationally in war
Installed	ground, shore fixed
Purpose	anti-air
Wavelength	300 cm
Peak Output	40 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	RE-3
Detected	aircraft, group at 250 km, single at 130 km
Weight	8700 kg
Number Built	30
Antennae	dipole array with mat type reflector, send and receive separate use

Type 12

Became Operational	April 1944
War Status	used operationally in war
Installed	ground movable
Purpose	anti-air
Wavelength	200 cm and 150 cm
Peak Output	5 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	RE-3
Detected	aircraft, group at 100 km, single at 50 km
Weight	6000 kg
Number Built	50
Antennae	dipole array with mat type reflector, send and receive separate use

Type 13

Detail of bridge structure of heavy cruiser Myoko at Singapore late in the war, the Type 13 radar mat is visible on top of the foremast
Became Operational	operationally March 1943, experimentally 1941
War Status	wide operational use in war
Installed	ground, surface ship and submarine portable
Purpose	anti-air
Wavelength	200 cm
Peak Output	10 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 100 km, single at 50 km
Weight	110 kg
Number Built	1000
Antennae	dipole array with mat type reflector, send and receive common use

Type 13 sets are known to have been installed on the following ships :

Major Ships

1941	month unknown	Oi, Kitagami
1943	June	Katori, Kashima, Kashii
	October	Yamato, Musashi
1944	May	Nachi, Ashigara, Haguro, Myoko
	June	Atago, Takao, Maya
	July	Junyo, Oyodo, Noshiro, Yahagi - 2 sets in Noshiro and Yahagi
	August	Amagi, Unryu
	October	Nagato, Katsuragi - 2 sets in the latter
	November	Sakawa - 2 sets
1945	January	Kitagami receives 2nd set

The experimental installations on Oi and Kitagami were probably the first examples of Imperial Navy shipborne radar. They were also the only Japanese ships to begin the war with radar installed.

Destroyers And Light Warships

1942	March	Kazegumo, Makigumo
	June	Naganami
	July	Akigumo, Yugumo
	August	Makinami, Takanami
	December	Onami
1943	January	Kiyonami
	March	Tamanami
	July	Fujinami, Hayanami, Suzunami
	October	Hachijo, Hamanami, Ishigaki, Kunashiri, Shumushu
	November	Asashimo
	December	Kishinami, Okinami
1944	February	D2, D8, D10, Hayashimo
	March	D4, D6, D12, D14, D16, D18, D20, D22,D24, Akishima
	May	D26, D28, Kiyoshimo
	June	Akebono, Amakusa, C1, C3, C5,C7, C9, C11, C13, C15, C17, C19, D30, D32, Etorofu, Fukue, Hibiki, Hiburi, Hirato, Kanju, Kasado, Manju, Matsuwa, Oki, Sado, Shikinami, Shimakze, Tsushima, Uranami, Ushio, Usugumo
	July	C21, C25, C27, C43, Shonan, Uhuru
	August	C29, C31, C33, D34, D38, D42, D44, D46, D130, Daito, Okinawa
	September	C23, C39, C51, C61, D52, D54, D56, D132, D134, Kume
	October	C35, C41, C63, C205, C207, D36, D50, D64, D66, D112, D138, Ikuna, Shinnan, Yaku
	November	C37, C47, C49, C53, C67, D60, D68, D72, D144
	December	Aguni, C45, C55, C69, C81, C215, D40, D74, D76, D82, D84, D118, D150, Chikubu, Inagi, Shisaka
1945	January	C57, C219, D102, D104, D106, Habushi, Sakito
	February	C59, C65, C213, D124, D154, D186, D190, D192, Kozu, Mokuto, Oga
	March	C71, C77, D48, D126, D156, D194, D196, D198, Hodaka, Kanawa, Shiga
	April	C73, C75, C221, D158, D200, Amami, Habuto, Ikara, Takane
	May	C79, C85, C87, C225
	June	C227
	July	C95, C217, D202, D204, Ikino
	August	C160
	November	D116
	month unknown	Kuga, Ugu

Type 14

Became Operational	May 1945
War Status	used operationally in war
Installed	shore line ground target type
Purpose	long range anti-air
Wavelength	600 cm
Peak Output	100 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 360 km, single at 250 km
Weight	30000 kg
Number Built	2
Antennae	unknown

Not put into operational use because the Type 21 was coming into service, with a weight of less than 1/30th of the Type 14, it was considered more practical for field use, even though Type 21 detected aircraft at reduced ranges.

Type 21

These 2 views of the superstructure of Ise taken after the war show the Type 21 aerial atop the main gun director
These 2 views of Aoba in sunken condition at Kure after the war show what may be a Type 21 radar aerial atop the foremast
Became Operational	August 1943
War Status	used operationally in war
Installed	surface ship
Purpose	anti-air, surface detection
Wavelength	150 cm
Peak Output	5 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	RE-3
Detected	aircraft, group at 100 km, single at 70 km, surface ship (large) 20 km
Weight	840 kg
Number Built	unknown, small number
Antennae	dipole array with mat type reflector, send and receive separate use

Once source indicates only 1 set of this type built, but same source indicates it was installed on numerous ships. At least 30-40 sets built and used operationally. Type 21 was the first Japanese air search radar that was power rotated, previous models had to be hand cranked to rotate. It was also the first set that gave good enough target definition to obtain rough estimates of height.

Type 21 was known to have been installed on the following ships :

Major Ships

1942	April	Ise
1943	January	Taiyo, Chuyo, Unyo
	November	Kaiyo
	December	Shinyo
1944	May	Nachi, Ashigara, Haguro, Myoko
	June	Atago, Takao, Maya
	July	Junyo, Oyodo
	August	Amagi, Unryu
	October	Nagato, Katsuragi - 2 sets in the latter

Destroyers

1943	March	Niitsuki
	May	Wakatsuki
	June	Akizuki, Hatsutsuki
1944	March	Shimotsuki
	May	Fuyutsuki
	June	Suzutsuki
	December	Harutsuki, Yoitsuki
1945	January	Hanatsuki
	Natsutsuki	Natsutsuki

Type 22

The shot of the escort Shonan in July 1944 shows the twin horns of the type 22 radar, abaft of the gun director part way up the foremast above it, one horn is slightly forward of the other
Became Operational	Became Operational: September 1944, see notes below
War Status	wide operational use in war
Installed	surface ships, submarines
Purpose	anti-air, surface dectection and gunnery control
Wavelength	10 cm
Peak Output	2 kw
Transmitter	magnetron
Receiver	crystal
Detector	n/a
Detected	aircraft, group at 35 km, single at 17 km, surface ship (large) 34.5 km
Weight	surface ships 1320 kg, submarines 2140 kg
Number Built	300
Antennae	horn type, send and receive separate use

In wide use by mid-to late 1944, Type 22 radar, while not designed for gunnery control, provided moderately accurate data for this purpose. Type 22 was the the type of radar that was most widely employed aboard ships and subs. It is known to have been installed on the following vessels :

Major Ships

1942	October	Kongo, Haruna, Hyuga
1943	June	Katori, Kashima, Kashii
	October	Yamato, Musashi - 2 sets each
1944	May	Nachi, Ashigara, Haguro, Myoko - 2 sets each
	June	Ise
	June	Fuso, Yamashiro may possibly have had Type 22 radar installed at this time
	July	Oyodo
1945	January	Kitagami

Destroyers And Light Warships

1942	March	Kazegumo, Makigumo
	June	Hamakaze, Naganami
	July	Akigumo, Yugumo
	August	Makinami, Takanami
	December	Onami
1943	January	Kiyonami
	March	Niitsuki, Tamanami
	May	Wakatsuki
	June	Akizuki, Hatsutsuki
	July	Fujinami, Hayanami, Suzunami
	October	Hamanami
	November	Asashimo
	December	Kishinami, Okinami
1944	February	D2, D8, D10, Hayashimo
	March	Akishima, D4, D6, D12, D14, D16, D18, D20, D22, D24, Shimotsuki
	April	Matsu
	May	D26, D28, Fuyutsuki, Kiyoshimo
	June	Akebono, C1, C3, C5, C7, C9, C11, C13, C15, C17, C19, D30, D32, Hibiki, Hiburi, Isokaze, Momo, Nowaki, Shikinami, Shimakze, Shiranuhi, Suzutsuki, Take, Ume, Urakaze, Uranami, Ushio, Usugumo and Yukikaze
	July	C21, C25, C27, C43 Kuwa, Shonan, Uhuru
	August	C29, C31, C33, D34, D38, D42, D44, D46, D130 Daito, Kiri, Maki, Okinawa, Sugi
	September	C23, C39, C51, C61, D52, D54, D56, D132, D134, Hinoki, Kashi, Kaya, Kume, Momi
	October	C35, C41, C63, C205, C207, D36, D50, D64, D66, D112, D138, Ikuna, Kaede, Shinnan, Yaku
	November	C37, C47, C49, C53, C67, D60, D68, D72, D144, Nara, Sakura, Tsubaki
	December	Aguni, C45, C55, C69, C81, C215, D40, D74, D76, D82, D84, D118, D150, Chikubu, Harutsuki, Inagi, Keyaki, Shisaka, Yoitsuki
1945	January	C57, C219, D102, D104, D106, Habushi, Hanatsuki, Nire, Sakito, Tachibana, Yanagi
	February	C59, C65, C213, D124, D154, D186, D190, D192, Kozu, Mokuto, Oga, Tsuta
	March	C71, C77, D48, D126, D156, D194, D196, D198 Enoki, Hagi, Hodaka, Kaki, Kanawa, Nashi, Shiga, Shii, Sumire
	April	Amami, C73, C75, C221, D158, D200 Habuto, Ikara, Kusunoki, Natsutsuki, Takane
	May	C79, C85, C87, C225, Hatsuzakura, Kaba, Odake
	June	C227, Hatsuyume, Iwo
	July	C95, C217, D202, D204, Ikino
	August	D160
	November	D116
	month unknown	Kuga, Uku

Submarines

The only one of the subs listed that I am 100% certain carried radar is the I-58, the others shown almost certainly did. It is likely that other subs had Type 22 radar installed late in the war. The dates of installation for most of these ships are as of commissioning. Only I-54 and I-56 would have had it installed later in the subs named below.

1944	7 September	I-58
	16 December	I-13
	30 December	I-400
	late 1944	I-54, I-56
1945	8 January	I-401
	14 March	I-15
	24 July	I-402

Airborne Search Radars

Type H-6

Captured G4M2 (Betty) in the markings of the Allied Tactical Air Intelligence Unit, the Yagi type antennae for the ASV radar is clearly visible protruding from the nose above the 7.7 mm machine gun, a second and smaller antennae can be seen on the rear fuselage protruding from about halfway between the 9 and 12 o'clock position of the UK roundel
Very difficult to see on this picture of a P1Y1 on a late war production line are the radar aerials, protruding from the nose and along the fuselage side through the Hinomaru
Became Operational	August 1942
War Status	used operationally in war
Installed	large flying boats, mid-sized attack planes (H8K, G4M2, P1Y, J1N1-S/11, J1N1-Sa/11a)
Purpose	air and surface search
Wavelength	200 cm
Peak Output	3 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 100 km, single at 70 km
Weight	110 kg
Number Built	2000
Antennae	Yagi type, send and receive common use

This set probably did not come into common use until 1944. Prior to that time any sets in use were probably deployed on H8K flying boats.

Type FM-1

Became Operational	September 1944
War Status	under preparation for practical use when war ended
Installed	four engine aircraft (H8K)
Purpose	air and surface search
Wavelength	200 cm
Peak Output	42 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 100 km, single at 70 km
Weight	70 kg
Number Built	unknown
Antennae	Yagi type, send and receive common use

Type N-6

The antennae for the radar on this B5N2/12 can be seen on the fuselage behind the Hinomaru, and on the wing leading edges, radar equipped planes of this type were used for ASW and patrol work, and not used as strike aircraft
This shot of a B6N2/12 after the war at Atsugi base near Tokyo shows the Yagi antennae protruding along the side of the rear fuselage, including from the Hinomaru
Became Operational	October 1944
War Status	experimental use
Installed	single engine 3 seat aircraft (B5N2/12 and E13A1b/11b ASW mods, B6N2/12, C6N1)
Purpose	air and surface search
Wavelength	120 cm
Peak Output	2 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 70 km, single at 50 km
Weight	60 kg
Number Built	20
Antennae	Yagi type, send and receive common use

Type FM-3

Not visible in this shot of the Q1W1/11 Tokai, Japan's only aircraft that was designed as a dedicated ASW patrol plane, are the antennae for the radar
This portion of drawing of the Tokai from "Japanese Aircraft of the Pacific War" by Rene Francillon (Naval Institute Press) shows the radar antennae nicely
Became Operational	June 1945
War Status	under preparation for practical use
Installed	single engine 3 seat aircraft (Q1W1/11 and Q2W2/21)
Purpose	air and surface search
Wavelength	200 cm
Peak Output	2 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 70 km, single at 50 km
Weight	60 kg
Number Built	100
Antennae	Yagi type, send and receive common use

Airborne Intercept Radars

FD-2

Became Operational	August 1944
War Status	not used
Installed	night fighters
Purpose	airborne detection and approach
Wavelength	25 kw
Peak Output	2 kw
Transmitter	cavity resonance
Receiver	2400
Detector	n/a
Detected	aircraft 3 km, surface ship 10 km
Weight	70 kg
Number Built	100
Antennae	Yagi type, send and receive separate use

While records list this type as officially not used, I find it hard to believe that in the desperate circumstances of the late war that many of those 100 sets did not find their way into Gekko or Ginga night fighters. Would certainly employed in at least small numbers in experimental capacity. Probably had antennae similar to the Type N-6 sets as shown above.

TAMA3

While records show this type of set as not having been operationally used in the war, this photo seems to refute that, being of a J1N1-Sa/11a Gekko of the 302nd Kokutai, the small glass dome on the nose containing the centimetric radar, I am guessing that this is the Tama3 set and not the FD-2, as the latter used a Yagi type aerial
Became Operational	July 1945
War Status	under preparation for practical use (saw active use)
Installed	night fighters (J1N1-S/11 and J1N1-Sa/11a)
Purpose	airborne detection and approach
Wavelength	200 cm
Peak Output	3 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft 3 km
Weight	70 kg
Number Built	10
Antennae	send and receive common use

As demonstrated in the picture, this type of set saw at least experimental deployment, and probably some operational use, even though records indicate it was still under preparation when the war ended.

Magnetic Anomoly Detectors

While not actually radar, the Japanese were unique in being the first combatant to employ a MAD, or magnetic anomoly detector, system. These devices allowed an aircraft to fly low over the water (about 60' in this case), and detect the disturbance in the Earth's magnetic field made by a submerged submarine.

Such devices are a staple of modern ASW warfare. Luckily for the Allied submariners, intraservice rivalry prevented the Jikitanchiki (as the device was called), from being paired with the Army's Ka-1 Autogyro. This near helicopter like aircraft could indeed hover, and combined with the MAD system would have been an extremely effective weapon against Allied subs.

Since the Army had modified and employed a few Ka-1's expressly for ASW work on their merchant aircraft carrier the Akitsu Maru, it shows the depth of the dislike between the two Japanes service branches that this connection of sensor system and aircraft were never made. Had they done so, the Japanese would truly have become the fathers of modern anti-submarine warfare, as the helicopter and MAD combination is used throughout the world today, in combination with sonobuoys which were not developed until after WW II.

When late in the war the Army finally either received some Jikitanchiki sets from the Navy, or developed MAD gear of their own, no one in the Army saw the possibilities of combining the hovering Ka-1 (normally used for artillery fire control) with the MAD system. Instead the Army installed their MAD systems on Ki-49-I heavy bombers that had been replaced in front line service and modified for ASW duty.

Jikitanchiki

Became Operational	by mid-1944, in common use by late 1944
War Status	used in war
Installed	Q1W1/11, Q2W2/21, B5N2/12 ASW mod, E13A1/11 and 11a ASW mod, Ki-49-I ASW mod
Purpose	detection of submarines
Transmitter	unknown
Receiver	unknown
Detector	unknown
Detected	submarines up to uknown depth, aircraft must be no more than 60' above water for Jikitanchiki to be effective
Weight	unknown
Number Built	unknown
Antennae	unknown, probably small numbers only

Search and Gunfire Control Radars

While it appears that the ground based anti-aircraft units received small numbers of radar sets for gunnery control, no true gunnery control radar seems to have been used aboard ships. While the Type 22 provided reasonably accurate ranges for gunfire, it had been designed as a search radar, and was relatively short ranged to boot. The longer range dedicated gunfire control radars under development appear never to have been installed operationally on ships.

Type 41

Became Operational	August 1943
War Status	used in war
Installed	ground anti-aircraft artillery
Purpose	anti-aircraft gunfire control
Wavelength	150 cm
Peak Output	13 kw
Transmitter	ring parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 40 km, single at 20 km
Weight	5000 kg
Number Built	50
Antennae	dipole array with mat type relector, send receive separate use

Type 42

Became Operational	October 1944
War Status	used in war
Installed	ground anti-aircraft artillery
Purpose	anti-aircraft gunfire control
Wavelength	150 cm
Peak Output	13 kw
Transmitter	ring parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group at 40 km, single at 20 km
Weight	5000 kg
Number Built	60
Antennae	Yagi type, send and receive separate use

Type 43

Became Operational	July 1945
War Status	used in war
Installed	ground searchlight units
Purpose	searchlight control
Wavelength	150 cm
Peak Output	13 kw
Transmitter	ring parallel two wire
Receiver	UN-954
Detector	n/a
Detected	aircraft, group and single at 40 km
Weight	500 kg
Number Built	121
Antennae	Yagi type, send and receive separate use

Type 23

Became Operational	March 1944
War Status	not used
Installed	surface ships cruiser or larger
Purpose	anti-surface ship gunfire control
Wavelength	60 cm
Peak Output	5 kw
Transmitter	cavity resonance
Receiver	2400
Detector	n/a
Detected	small surface ships 13 km
Weight	1000 kg
Number Built	unknown
Antennae	parabola, send and receive common use

Type 31

Became Operational	March 1945
War Status	under preparation for practical use
Installed	ground shore batteries, surface ship cruiser size or larger
Purpose	anti-surface ship gunfire control
Wavelength	10 cm
Peak Output	2 kw
Transmitter	magnetron
Receiver	crystal
Detector	n/a
Detected	large surface ships 35 km
Weight	1000 kg
Number Built	unknown
Antennae	parabola, send and receive common use

Type 32

Became Operational	September 1944
War Status	under preparation for practical use
Installed	ground shore batteries, heavy cruisers and battleships
Purpose	anti-surface ship gunfire control
Wavelength	10 cm
Peak Output	2 kw
Transmitter	magnetron
Receiver	crystal
Detector	n/a
Detected	large surface ships 30 km
Weight	5000 kg
Number Built	60
Antennae	square horn, send and receive separate use

Type 33

Became Operational	August 1944
War Status	not used
Installed	surface ships
Purpose	anti-surface ship gunfire control
Wavelength	10 cm
Peak Output	2 kw
Transmitter	magnetron
Receiver	crystal
Detector	n/a
Detected	small surface ship 13 km
Weight	800 kg
Number Built	unknown
Antennae	round horn, send and receive separate use

Radar Guidance Units (Navigational and Detection Radar)

Among the sets covered by this category are ESM warning receivers, which detected enemy use of radar rather than sending out active detection itself. While the models indicated here don't enter service until April or May of 1944, it is clear the the Imperial Navy had some type of shipboard detector used first in the Solomons in 1943 (possibly even as early as late 1942).

Type 61

Became Operational	April 1945
War Status	under preparation for practical use
Installed	important ground area
Purpose	enemy aircraft height and position measurement
Wavelength	60 cm
Peak Output	10 kw
Transmitter	shielded oscillator
Receiver	2400
Detector	n/a
Detected	single aircraft 130 km
Weight	15000 kg
Number Built	1
Antennae	parabola, send and receive common use

Type 62

Became Operational	June 1945
War Status	under preparation for practical use
Installed	important ground area
Purpose	friendly aircraft position measurment
Wavelength	200 cm
Peak Output	10 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	n/a
Detected	single aircraft 100+ km
Weight	3000 kg
Number Built	1
Antennae	dipole array, send and receive common use

Type 63

Became Operational	unknown, possibly never
War Status	under preparation for practical use
Installed	important ground area
Purpose	long distance enemy position measurement
Wavelength	300 cm
Peak Output	40 kw
Transmitter	parallel two wire
Receiver	UN-954
Detector	RE-3
Detected	single aircraft 160 km
Weight	8700 kg
Number Built	1
Antennae	dipole array, send and receive common use

TH

Became Operational	July 1945
War Status	not used
Installed	shore installations
Purpose	special attack boat guidance
Wavelength	150 cm
Peak Output	13 kw
Transmitter	ring parallel two wire
Receiver	UN-954
Detector	n/a
Detected	small surface ship/attack boat less than 20 km
Weight	500 kg
Number Built	unknown
Antennae	diplose array, send and receive common use

The purpose being stated as "special attack boat guidance" indicates that these sets would probably have been installed near expected points of invasion to direct counterattacks by Shinyo suicide boats against the transports of a landing force.

M-13

Became Operational	June 1945
War Status	not used
Installed	all types of aircraft
Purpose	IFF general aircraft use
Wavelength	200 cm
Peak Output	0.05 kw
Transmitter	coil and capacitor
Receiver	UN-955
Detector	n/a
Detected	100 km from a small surface ship/attack boat
Weight	10 kg
Number Built	100
Antennae	bendback 1/4l

Type 51

Became Operational	unknown, possibly never
War Status	not used
Installed	four engine bombers
Purpose	navigational?, target detection?, large bomber use
Wavelength	10 cm
Peak Output	6 kw
Transmitter	magnetron
Receiver	crystal
Detector	n/a
Detected	unknown, possibly earth or ocean surface search, 20 km
Weight	200 kg
Number Built	unknown
Antennae	parabola, send and receive common use

FH-1

Became Operational	February 1945
War Status	used in war
Installed	large flying boat (H8K2)
Purpose	low altitude radio altimeter
Wavelength	88 cm
Peak Output	0.0001 kw
Transmitter	parallel two wire
Receiver	UN-955
Detector	n/a
Detected	earth or ocean surface .015 km
Weight	30 kg
Number Built	100
Antennae	double T

E-27

Became Operational	April 1944, prototypes probably saw frontline use in Solomons Campaign
War Status	used in war
Installed	torpedo attack boat (destroyer)
Purpose	ESM warning indicator
Wavelength	75-400 cm
Peak Output	n/a
Transmitter	n/a
Receiver	UN-955
Detector	n/a
Detected	enemy radar/radio use 300 km
Weight	40 kg
Number Built	2500
Antennae	unknown

Unknown Type

Became Operational	unknown, probably never
War Status	unknown, probably not used
Installed	ground, surface ship
Purpose	ESM warning indicator
Wavelength	3-75 cm
Peak Output	n/a
Transmitter	n/a
Receiver	unknown
Detector	n/a
Detected	enemy radar/radio use unknown range
Weight	unknown
Number Built	200
Antennae	unknown

FT-B

Became Operational	May 1944
War Status	under preparation for practical use
Installed	bomber and reconnaissance aircraft (P1Y, G4M2, H8K2, etc.)
Purpose	airborne ESM warning indicator
Wavelength	45-370 cm
Peak Output	n/a
Transmitter	n/a
Receiver	UN-955 x 2
Detector	n/a
Detected	enemy radar/radio use 300 km
Weight	20 kg
Number Built	300
Antennae	unknown

FT-C

Became Operational	May 1944
War Status	under preparation for practical use
Installed	bomber and reconnaissance aircraft
Purpose	airborne ESM warning indicator
Wavelength	45-370 cm
Peak Output	n/a
Transmitter	n/a
Receiver	UN-955 x 2
Detector	n/a
Detected	enemy radar/radio use 300 km
Weight	20 kg
Number Built	100
Antennae	unknown

Totals

30 different types of radar were built by the Japanese during WW II, with a total of 7256+ sets of all types built.

Conculsions

While the Japanese had been the first to develop radar among the major combatants, they were the last to enter into a serious effort to develop this important device for military purposes. As best I can tell, Imperial Army and Navy officers who were exposed to radar prior to the war failed to grasp its significance, and never bothered to press for its development. This lack of understanding what radar represented to wartime operations would cost the Japanese much in the way of lost aircraft, ships and men. Imagine for instance a Japanese carrier force at Midway warned by air search radar of the approach of the American dive bombers, and you can see how easily the course of critical battles might have been resolved more favorably to the Japanese if they had effective radar early in the war.

The other lacking that seems to have been prominent in the Japanese radar development effort is the failure to develop specialized radars such as the fighter direction radars carried aboard the American carriers. While the Japanese had a good program underway when the war ended, their lack of early effort meant that they were always behind the Allies in their advances. Japanese radar of 1945 was roughly equivalent to that employed by the US in 1942 and 1943, while at that point the Americans and British had advanced fire control radars in common service with both anti-ship and anti-air capability. By the end of the war the Americans were also expert in the use of radar to vector combat air patrol onto incoming attackers, making their fighters far more effective.

The Battle of Surigao Straight as part of the larger Leyte Gulf clash demostrates how devestating the lack of specialty control radars could be. The Japanese battleships Fuso and Yamashiro, escorted by a heavy cruiser and several destroyers came at a much stronger American force in a night battle that resulted in the Japanese being crushed with almost no damage to the US ships. The main advantage the Americans had outside of numbers was accurate, long range detection and fire control radars. This allowed the American ships to annihilate the Japanese force before it ever had a chance to seriously engage them.