as frequency counts, were useless. They purchased a commercial version of the Enigma, but it too was useless.  The commercial machine used four rotors to cipher the letters and had  no plugboard. The German military had made too many changes to the machine for the Poles to make use of the commercial Enigma.

Determining the exact wiring of each of the three rotors became the Polish cryptanalysts' first task. To accomplish this, Poland's cipher bureau tested and hired three mathematicians in 1932. Marian Rejewski, Jerzy Rozycki, and Henryk Zygalski painstakingly analyzed the intercepted encrypted messages searching for clues. Rejewski eventually determined a mathematical equation that could find the wiring connections.