Nyorera kupfuurira kweiyi ndima - Soviet Union yakapinda muPoland muna September 1939 pasi peMolotov-Ribbentrop Chibvumirano neGermany; Soviet Union yakapinda muFinland
muna November wa1939; muna June wa1941, Germany yakabvisa chibvumirano chokusarwisa ndokupinda muSoviet Union. Kunyange zvazvo USSR yakanga ine masayendisiti uye mainjiniya akatanhamara, yakatanga kutsvakurudza pane zvaizova radar ("radiolokatsiya", lit. radiolocation) nokukurumidza somunhu upi noupi zvake, uye yakafambira mberi zvakanaka nekutanga kwekugadzirwa kwemagnetron, yakapinda muhondo isina nzvimbo, yakakwanisa zvakakwana radar system.