The 6th Bomb Group

Shimonoseki Straits today.  Much of the Japanese shipping went through these straits.

This was a night mining mission, involving 29 planes of the 6th Bomb Group:

The first mission of this nature was flown to reinforce mine fields in the Shimonoseki Straits area. Flak was heavy and one plane was shot down. The crew and aircraft lost was commanded by Capt Schmid and carried as a combat observer, Lt Col Dixon. Reports from members of other crews on the mission reveal that one B-29 in the formation was caught in a number of searchlights, sustained several direct flak hits and was seen to spiral down and crash in flames. Since the Sixth was the only group operating in the area, it is a reasonable assumption that this was Capt Schmid's plane.

[Pirate's Log, p. 49]

According to the Distinguished Unit Citation:

On the night of 9 July 1945, ninety-seven percent of the 31 aircraft airborne effectively mined their assigned target areas, with the loss of one aircraft.  For tactical reasons, the aircraft were flown at reduced speeds and at low altitude over the heavily defended areas of Yawata and Shimonoseki Straits, encountering as many as twenty-five searchlights coned on a single aircraft, coordinated with heavy, intense and accurate flak.  In spite of these overwhelming obstacles, the briefed courses were unerringly held and the mines were dropped in the exact assigned positions, confirmed by radar scope photographs.

A view of the Shimonoseki Straits today facing east.

20th AF Mission 256

Date: 9/10 July 1945
Target: Shimonoseki Straits, Niigata and Nanao
Participating Units: 313th BW
Number A/C Airborne: 31
% A/C Bombing Primary: 93.55% (29 Primary and 1 Alternative)
Type of Mines Used: MK26-36, 1000#, and MK25, 2000# mines with various settings.
Tons of Mines Planted: 193 tons Primary and 7 tons Alternative
Time Over Primary: 100102K - 100317K
Altitude of Attack: 6,900 - 8,800
Weather Over Target: 0/10 - 9/10
Total A/C Lost: 1
Resume of Mission: It was believed that Feshiki and Niigata harbors were closed for approximately 4 days and the areas mined in the straits were unusable for 1 week. Of the 274 mines dropped, it was estimated 267 were effective. One A/C was non-effective. Eighteen E/A sighted made 4 attacks. Flak was heavy, moderate to intense and accurate over Shimonoseki and meager and inaccurate at others. The A/C lost was shot down by flak and E/A over the mining field. Eight B-29s damaged by flak. Nine A/C landed at Iwo Jima. Average mine load: 12,605 lbs. Average fuel reserve: 530 gallons.