TheCodeBreakers
the battle against the southern force, commanded by General Aleksandr
Samsonov. To do so would almost ensure victory, but it would also leave
the German rear entirely unprotected from an attack by Rennenkampf.
While the German staff was discussing the pros and cons of this move on
the evening of August 24, a motorcyclist brought in two Russian
intercepts. They had been forwarded on the initiative of the head of the
radio station at the German fortress at Konigsberg. His operators, who
had little traffic of their own to transmit, had begun listening in to the
Russian transmissions as a diversion.
Both messages were from the headquarters of Samsonov's XIII Corps,
which was communicating with army headquarters by radio because
that was the only means the corps had. And both were in the clear
because XIII Corps had never received the proper cipher key. They
specified exactly where the corps was going, when it expected to be there,
annaabi.ee 
