Battle of Huoyi

Timeline

1. 617Huoyi · ShanxiAfter raising his army at Jinyang, Li Yuan marched south. Sui general Song Laosheng held Huoyi with a large force, controlling the Fen River valley road that was the only route into Guanzhong, forcing the Tang army to decide whether to assault it.
2. 617Outside Huoyi · ShanxiLi Shimin, Li Jiancheng, and others led the Tang army in fierce fighting against Song Laosheng's forces at Huoyi. The Tang troops charged bravely, broke the Sui battle lines, and Song Laosheng was defeated and killed, dealing a heavy blow to the Sui main force.
3. 617–618Fen River valley · ShanxiAfter the great victory at Huoyi, the Tang army advanced east along the Fen River valley, capturing Linfen and other places in succession, clearing the main military obstacles on the road east to Chang'an and laying the foundation for entering the pass.