TheCodeBreakers
Novikov's lengthy
report of his reconnaissance of Central Powers troops, with his
additional note: "I took the decision of not crossing the Vistula." The
message was dated 8:40 a.m.; by 4 p.m. the Austrian liaison officer had
brought it to the attention of the German headquarters. Knowledge of
Novikov's decision determined the initially successful Austro-German
tactics of the battles of the Vistula and San rivers. Other intercepts were
valuable in more local situations. A message of Prince Engalitschev,
colonel of the 10th Russian Cavalry Division, warned of a strong attack
on the fortress of Przemysl; the prepared commander easily warded it off
until the Austrian advance forced the Russians to lift the siege in mid-
October. During this advance, Pokorny's group solved as many as 30
cryptograms a day.
It was at about that time that the Russians made their first key
change. It apparently consisted only of altering the order in which the
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