From The Asahi Shimbun, 10 May 2015
OSAKA–An unexploded bomb believed to have been dropped by U.S. forces in a World War II air raid was defused and removed by the Self-Defense Forces in a busy shopping district here on May 9.
The work forced the evacuation of residents in the Minami shopping district of Osaka’s Naniwa Ward and disrupted morning train services.
“It is extremely rare for an unexploded bomb to be found in a bustling shopping area in central Osaka,” said an official of the Osaka city government’s crisis management office.
According to the Osaka city government, the U.S.-made bomb weighs one ton and measures 1.8 meters in length and 60 centimeters in diameter. It was found at a construction site of a new condominium building in March about two meters below ground.
The work to remove the bomb was started at around 8 a.m. by troops specializing in the disposal of unexploded ordnance. They were dispatched by the Ground SDF’s Katsura post in Kyoto.
An area within a radius of 300 meters (984 feet) from the site was designated an evacuation zone, with about 2,200 residents ordered to evacuate. Of these, 114 took shelter at two nearby elementary schools. The Nipponbashi area of electric appliance stores was designated off limits and traffic around the area was also restricted.
After the troops defused the bomb, the evacuation order and traffic restrictions were lifted at 9:36 a.m.
Nankai Electric Railway Co. suspended operations of a total of 167 trains that were scheduled to depart from or arrive at its Nanba Station, inconveniencing about 48,000 passengers. It resumed services at around 10 a.m.
According to the public-interest organization Osaka International Peace Center, known as Peace Osaka, U.S. forces conducted more than 50 air raids on Osaka Prefecture from December 1944 to August 1945, killing more than 15,000 people.
The city’s crisis management office said a total of 87 dud bombs, apparently dropped by U.S. forces, have been found in Osaka since 1955, including the one that was removed on May 9.
Osaka Air Raids Assessment: The bomb that was removed was a 2,000-lb general purpose bomb, the AN-M66 type, introduced into service in 1943. This weapons is about 5.9 feet long (1.8m) and 24 inches wide (60cm). Although it weighs 2,000 pounds (907kg) the explosive filler accounts for about 1,061 pounds of that weight (481kg).
It was designed for use against “massive reinforced concrete and suspension bridges, heavy cruisers, battleships, dams,” according to an aerial bomb chart on the 303rd Bomb Group (H) website. The minimum safe BA (blast area?) for the bomb is 3,000 (probably a measurement feet).
B-29 Superfortress very heavy bombers employed this weapon on occasion against targets in Japan. In the case of air raids on Osaka, from XXI Bomber Command summaries it appears these weapons were dropped on Osaka at least three times, on 26 June 1945, 24 July 1945 and 14 August 1945, in attacks aimed at the vast Osaka Army Arsenal complex adjacent to Osaka Castle, which was Imperial Japan’s largest army arsenal.
26 June 1945 – Mission 224. Target: Osaka Army Arsenal, Target Number 90.25 – 382. 73rd Bomb Wing Superfortresses employed AN-M66 2000-lb bombs with 1/40 second delay fusing on nose and tail. A total of 109 B-29’s hit the primary target and three others struck targets of opportunity, with an average bomb load of 14, 402 pounds. Flak was heavy, medium and inaccurate. P-51’s were sighted in the target area, which probably kept some Japanese fighters away though 12 enemy fighters were sighted and seven made attacks on the bombers. Aerial gunners claimed one enemy fighter destroyed and one damaged in the attacks. With weather 10/10 cloud, all bombing was by radar. The time the B-29’s were over the primary was nearly an hour, from 1018K to 1116K (one hour ahead of Japan local time), and the aircraft bombed from 17, 400 feet on up to 29,060 feet in altitude. Detonations were observed immediately northwest of the castle and about 2,000 yards south of the target. One B-29 was lost to unknown causes.
That aircraft was B-29 serial number 44-69655, which belonged to the 499th Bomb Group (VH), 877th Bomb Squadron, flown by the Capt. James F. Newell crew (11 members total). This ship was not seen enroute or in the assembly weather due to poor weather conditions, and was last heard from at 0950K in the assembly area. Cause of loss is unknown (MACR 14911). The crew was initially declared MIA and later classified as KIA.
Their ultimate fate was learned after the war. The aircraft was apparently shot down, by Japanese fighters, according to one source, after attacking Osaka Arsenal and crashed near Miyaka Village (absorbed into Hidakagawa Town in 2005) in Hidaka County, Wakayama Prefecture, about 60 miles south of the target. Two crew members were KIA (Capt. Newell and S/Sgt John S. Combs), and the remaining nine became POWs, who were taken to the Osaka Kempei Tai (the military police arm of the Imperial Japanese Army and essentially a dreaded secret police) headquarters. First Lt. David W. Cobb, 1st Lt. Paul L. Sisson, T/Sgt Leo G. Copulos, S/Sgt John N. Wall, Sr., S/Sgt Howard F. Woleslagle and Sgt. Raymond F. Shiber were executed or died from disease. S/Sgt Robert L. Pellicot and 1st Lt. Louis W. Lehnen were executed on/about 5 August 1945 at the Jonan rifle range in Osaka City. First Lt. Harold T. Cobb was executed at the Sandayama Military Cemetery in Osaka City on 15 August 1945, the day the fighting in the Pacific was supposed to end.
24 July 1945 – Mission 286. Target: Osaka Army Arsenal, Target Number 90.25 – 382 as the primary visual target, with the city of Kuwana near Nagoya (Tgt # 90.20) as the primary radar target. The 73rd Bomb Wing employed AN-M66 2000-lb bombs with 1/40 second delay fusing on nose and tail. The wing again faced cloud impediment to visual aiming with a solid undercast but 35 aircraft pressed to hit the Osaka Arsenal with 216 tons of bombs; most aircraft (119) delivered weapons on the primary radar target (794 tons), with another nine striking targets of opportunity with 59 tons of bombs. Weapon impacts were noted in the target area, and immediately south and west of the target and Osaka Castle was struck. Of the 216 M66 bombs dropped on Osaka Arsenal, 28 struck within 1,000 feet of the Mean Point of Impact. Over Osaka flak was moderate, accurate and continuously pointed. No enemy fighters were sighted – at this point Japan was trying to conserve its air strength for the anticipated battle for the Hone Islands. The target was struck from altitudes ranging from 19,900 feet to 23,000 feet, between 1144K and 1227K. No B-29’s were lost on this mission, though 46 bombers were damaged by flak received at various points all along the mission route. Post-attack reconnaissance indicated another 8.4% of the arsenal was damaged, raising the total amount of damage/destruction to 18.1 %.
14 August 1945 – Mission 326. Target: Osaka Army Arsenal, Target Number 90.25 – 382. The 73rd Bomb Wing again employed AN-M66 2000-lb bombs with 1/40 second delay fusing on nose and tail, as well as half-ton AN-M65 1,000-lb bombs. This time the target was acquired visually and bombed by 145 B-29’s dropping 706.5 tons of bombs with excellent results – strike photos taken by 36 aircraft showed 650 hits on the target. Of 843 bombs dropped, 216 hit within 1,000 feet of the aimpoint. The attack occurred between 1416K and 1501K. Bombs were dropped from between 22,100 and 25,100 feet. The average bombload was 10, 924 pounds. Two B-29’s dropped 10 tons of bombs on targets of opportunity. The average bombload was 14, 301 pounds. Flak was heavy, moderate, generally accurate and continuously pointed and 26 B-29’s were damaged by it. P-47 and P-51 fighters provided escort but no enemy aircraft were sighted. No B-29’s were lost on the mission.
From the description of the three air raids that employed the AN-M66 2000-lb GP bomb, perhaps the raid of 26 June 1945 is the one which delivered the bomb in the Minami shopping district of Naniwa Ward that was removed on 9 May 2015. Some weapons were noted striking a mile south of the target area. The raid of 24 July 1945 saw few aircraft attack the arsenal, and on the 14 August 1945 raid the bombing was visual and results excellent, so under such conditions there were probably not many weapons which strayed far from the target area.
But whenever that bomb arrived, let’s give thanks to the explosive ordnance disposal professionals who successfully and safely removed this long dormant aerial weapon before it could cause any death or injury!
Asahi article at: http://ajw.asahi.com/article/behind_news/social_affairs/AJ201505100021
M66 replicas in Osaka Peace Museum at: http://www.snipview.com/q/Osaka_International_Peace_Center
73BW/500BG (Z) B-29 and bombs image: http://www.freerepublic.com/focus/news/3290704/posts
June 1945 B-29 Mission Summary, at: http://user.xmission.com/~tmathews/b29/56years/missionsummary4506.html#15jun45
July 1945 B-29 Mission Summary, at: http://user.xmission.com/~tmathews/b29/56years/missionsummary4507.html
August 1945 B-29 Mission Summary, at: http://user.xmission.com/~tmathews/b29/56years/missionsummary4508.html
MACR 14911, access via Fold3 website
Mann, Robert A., The B-29 Superfortress Chronology, 1934-1960, McFarland, 2009, page 188
Loss of B-29 44-69655 on 26 June 1945, summary at: http://user.xmission.com/~tmathews/b29/56years/56years-4506b.html