The original Yak-9 went into production in October 1942 and entered service in December with 42 IAP in the defence of Stalingrad. Only 500 over the original Yak-9s were built before it was supplanted by the modified variants the first being the Yak-9T.
The first Yak-9T with the 37mm cannon first entered service at the end of March 1943 and saw action at Kursk with units of the 16th Air Army.
<S>...-Gixer