Razzles - Firing the Grunewald Forest

R.A.F. Fires German Forests

– The New York Times, September 5, 1940 –

Photo: John Frost newspapers.

In the late summer of 1940, while the Battle of Britain was raging overhead, Commander-in-Chief of RAF Bomber Command Air Marshal Charles Portal directed a new strategy to his squadrons. So, following the first “retaliation” bombing offensive against Berlin during the last week of August [see previous posts posted here], London tested new ways to strike the heart of the Reich.

The idea behind Operation Razzle, one of the lesser known campaigns of the Second World War, was to burn Germany’s forests and crops with a new —and simple— weapon known as ‘calling cards’ (small treated cardboards) which, once dry ignited in contact with air exposure and burn rapidly with a hot flame. British aircraft would scatter these incendiary ‘leaves’, usually dropped by Whitley or Wellington bombers by night at low level, over areas of the Black Forest and other large forests where it was believed by British Military Intelligence that weapons and other military stores were being concealed, as an Air Ministry communique released on those days related: “are designed to get fire to military stores standing in the open at arsenals and ammunition factories or to supplies in open railway cars or trucks and similar objectives. It is know that the enemy has concealed such targets in woods.”[1] 

In reality, this new tactic was part of the British economic war against the Reich, intended to destroy the enemy’s crops, grain fields and lumber-producing woods. With the imminent German invasion of the British Isles Bomber Command’s number one priority was the struggle against the enemy landing fleet menace across the Channel, however, in directives issued by the Air Ministry throughout the summer attacks were ordered on the Nazi oil industry, communications, forests and crops.[2] Moreover, as early as June the bombing force was warned to be ready to set alight forests and woods using a new incendiary device soon to be available.[3] 

First ‘Razzles’ were dropped on the night of 30 June. That first night nearly ended in tragedy when one of the RAF raiders, after first bombing their primary target, proceeded to the Black Forest area in southwestern Germany and drop the cards. However, some of the leaves caught in the aircraft’s slipstream, were blown onto the tailplane elevators causing minor fires with the bomber returning with severe damage to base.[4]

First specific raid was on 2/3 September night when ten Wellingtons of No 214 Squadron were sent to fire bombings in an area forests between the Havel lake and Falkensee and NW of the Tegel sea outside the German capital.[5] Interestingly, looking into the Group’s Orders a clear recommendation can be found: “attacks on forests areas to be made in such a manner as will be best helped by prevailing wind conditions.”[6] On the next night, six sorties were made attacking the Grunewald Forest in Berlin too, while six others bombed the Black Forest.[7] These fire bombings were repeated again on the next night, September 5th.[8]

[‘Razzles’ were usually dropped through the flare chute of the aircraft, same way that leaflets were on ‘Nickelling’ sorties. Here, one of the aircrew of a Whitley bomber of No 102 Squadron demonstrates how propaganda leaflets are dropped.]

Photo: © IWM (C 826)

Incendiary cards ‘a British weapon’
This new weapon was developed in 1938 by London scientifics (others say it was an American idea) but resulted in a great failure due to German forests and fields were too green and moist, they did not catch fire cause they required tinder-dry vegetation and the northern European weather wasn’t very favourable either.

Three types of these fire raising’ devices were used: ‘calling cards’ (chemically treated cardboard sizing 75x25mm), ‘Razzle’ (small plates of cellulose nitrate plastic) and ‘Decker’ (same but larger size). All of them worked in the same way: after several hours on the ground the phosphorous dried out and ignited the celluloid, which burned for thirty seconds and so set on fire its surroundings. Furthermore, in the case if was dropped during wet weather it was believed that these cards may not ignite until several days after they hit the ground. As long as the cards were immersed in water they were incombustible, so usually were stored in tins of alcohol or water inside the bomber[9] about 450-500 to a tin.

British authorities admitted their use and described the weapon at the time just as a “self-igniting leaf”[10] but we can find a deeper description on the Popular Science issue of October, 1942: “scatter-type phosphorus missiles have been designed by the British to set fire to enemy crops and lumber-producing forests. German patience, so often exhausted, must have plumped to a new low when R.A.F. raiders began sowing these incendiary ‘calling cards’ over the countryside a couple of years ago. A single plane carries as many as a quarter of a million of them. Each three-inch-square card contains a pad impregnated with phosphorus, moistered to delay its taking fire, which it would otherwise do immediately. The resulting flame, about eight inches long, suffices to touch off grain or forest undergrowth within its reach.”[11]

Photo: Popular Science. A Technical Journal of Science and Industry. VOL 141, No 4. Oct 1942. Popular Science Publishing.

[A German propaganda picture showing a pair of incendiary cards dropped by RAF aircraft, September 1940. The original caption reads: “These are the weapons of the British night pirates! Enormous amounts of detonating leaflets dropped over German areas - since August 11, 1940, so-called incendiary leaflets were first scattered and then in enormous quantities by English planes on their cowardly night flights over Germany over long distances of our country.”]

Photo: akg-images/Sammlung Berliner Verlag.

BRITISHCALLING CARDDROPPED BY R.A.F. IN GERMANY”:  the picture was published in some US papers in the following days too, describing the weapon and its effects to woods and fields. It seems however, that the innocent-looking discs caused, according to the Neue Frankfurter Zeitung, much more damage to people than to crops: many souvenir-hunting Germans received an unpleasant shock after placing the leaves in their trouser pockets. In fact, Nazi authorities described the tiny cards as “poisoned” with the admonition to mothers that they should warn their children against picking them up and accused the new British weapon to be “directed against the German youth, the German harvest and the hard-earned property of the German people.”[12]

Photo: The New York Times, September 13, 1940, page 4

On these Razzle sorties British bombers dropped the fire-cards mixed with ordinary incendiary bombs (on some raids only fire bombs were dropped), usually the early 25-lb type parachute bomb as we can read on some of the Squadrons’ ORBs describing the required bombload: “six containers of 25 lb parachute incendiary bombs, the maximum load being made up with 250 lb light case incendiary bombs.”[13] Similar in shape to the 250-lb GP bomb and considered a large incendiary bomb, the 25-lb ‘Firepot’ was very unsatisfactory and quickly replaced after the first year of use by new and more effective IBs as was the 4-lb weapon.[14]

[The 25-lbs (12,5 Kg) incendiary bomb seen here in both German (at left) and British (right) drawing diagrams made during the wartime years.]

Photo: Hilske, M/ Bolan, GT, 1946.

This is an original ww2-footage showing an unexploded incendiary 25-lb bomb (“English fire bomb fell into the open field”)  after being dropped by British bombers during a raid on Germany on September 6, 1940, with the bomb falling on open field. The video was part of German propaganda newsreel which shows bomb damage in the city of Bruchsal following an attack by the Royal Air Force on the night of September 20, 1940. A soldier kneels next to a bomb stuck in the ground and pulls out the unopened parachute of the bomb.

Video source: Haus des Dokumentarfilms. Kinemathek Oberrhein.

Bomber Command’s campaign to drop firebombs over German forests and crops was limited to a few isolated raids during the late summer of 1940. Although British and American press defined the operation as a “mass firing” and “new secret weapon dropped in millions”, describing the effects of the fires during those raids as very successful (“Damp Discs, Dropped by R.A.F. by Thousands, Dry and Ignite–Nazis Incensed” can be read on a New York Times headline)[15] the true was that just a few fields had been burnt and that the fire didn’t spread much and as fast as desired and following the first sorties, London quickly decided that Razzle did not possess war-winning potential, and was consigned to the ‘It was worth to try’ file. The strategy was tried again on 1941 but was disappointed one more time and was abandoned.

With the invasion of England being threatened, Nazi barges in the Channel ports were a much higher priority target and so were the focal point for the Command’s attention during September.[16]



[1] The New York Times, Associated Press, September 11, 1940, page 1
[2] YOUNG, Neil. The Role of the Bomber Command in the Battle of Britain. Imperial War Museum Review No. 06, 1991 (accessed June 2023)
[3] ibid
[4] DELVE, Ken. Vickers Armstrong Wellington. The Crowood Press, 1998, p 28. See also The Battle Of Britain Weather Diary, 11th August 1940 (accessed June 2023)
[5] see The National Archives of the UK (TNA): AIR-27-1235 © Crown Copyright
[6] ibid
[7] see TNA: AIR-27-894_2
[8] see TNA: AIR-27-1235
[9] Command and General Staff School Military Review. “Plastics in new uses”. Volume XXI 1941. Number 83, March 1941. p 55; DELVEop. cit. p 28
[10] The New York Times, Associated Press, September 11, 1940, page 1
[11] Popular Science, “Phosphorus”, Vol 141, No 4, October 1942, pp 108-112
[12] The New York Times, Associated Press, September 11, 1940, page 1; RICHARD, Denis. Royal Air Force, 1939-1945, Vol I: The Fight at Odds. German Blockade, British Bombing, p 238
[13] see TNA: AIR-27-894_2
[14] BOLAN, G T. The development of British incendiary bombs during the period of the 1939-45 World War. Armaments Design Establishment Technical Report. Ministry of Supply.
December 1946; nearly 20,000 of the 25-lb bomb were dropped during the war: BURLS, Nina. RAF bombs and bombingROYAL AIR FORCE HISTORICAL SOCIETY. Journal 45. 2009
[15] The New York Times, Associated Press, September 11, 1940, page 1
[16] Britain at War. From First to Last. (accessed June 2023)


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