Siping is initially held by the Nationalist forces and the Red Army, but the Red army is due to move out. The Nationalist forces don't have the man power to hold it until reinforcements can arrive and so hire a number of gangs to bolster the garrison.
It is recommended that the Red Army units move out and off board (to the edge out of the way) by turn 5.
The Nationalists gangs take a pre-emptive strike against the Communist forces but are repelled and destroyed.
The Communist forces then take the opportunity to attack several villages including Crouching Tiger Village, Maolin, Baokang and Twin Mountains.
They then move towards Siping, siege it and then attack it, destroying the Nationalist forces.
Historically the Nationalists high command were furious and sent reinforcements made up mainly of mechanised units, however they never arrived due to the weather and snow melt. However, in this scenario the are set to arrive on the board edge between turns 20 and 25 so you can see what effect that would have had on things