The Battle on the Pyana River involved a confrontation between the Blue Horde, a division of the Golden Horde led by Khan Arapsha, and the forces of the advancing Russian principalities. The growing strength of these principalities posed a notable threat to the Mongol dominance that had existed in the region for several decades. The battle took place along the banks of the Pyana River, allowing the Blue Horde to utilize their cavalry's mobility effectively, which was critical in the fast-paced skirmishes typical of Mongol warfare.

In the lead-up to the battle, tensions had escalated as Russian territories sought to assert their independence from the Mongol rule, leading to increased military engagements. The Blue Horde's forces, numbering in the thousands, engaged the Russians, who were less experienced in maneuver warfare. A series of charges by the Khan's cavalry broke the Russian lines, resulting in a decisive victory for the Blue Horde and reaffirming their control over the region.

This battle not only represented a crucial military victory for the Blue Horde but also served as a significant moment in the ongoing struggle between the declining Mongol influence and the rising power of the Russian states in the late 14th century. The victory slowed the momentum of Russian expansion, impacting the political landscape in Eastern Europe and contributing to the eventual realignment of power in the region over subsequent decades.