Both the Zygalski-sheet method and each bomba worked for only a single scrambler rotor order, so six sets of Zygalski sheets and six bomby were produced [REF].
When World War II broke out on 1 September 1939, Leśniak and his colleagues had been working intensively for two or three years to establish the German order of battle and had succeeded in working out nearly 95 percent of it.