Germany immediately found ways not to keep to these conditions. A secret collaboration with the Soviet Union began after the treaty of Rapallo. Germany helped the Soviet Union with industrialisation and Soviet officers were to be trained in Germany. German tank and air force specialists could exercise in the Soviet Union. German chemical weapons research and manufacture would be done there, plus other projects. Around three hundred German pilots received training at "Lipetsk", some tank training took place near "Kazan" and toxic gas was developed at "Saratov" for the German army.