Introduction:
The Peshwas were the prime ministers of the Maratha Empire and played a significant role in expanding and consolidating Maratha power. After the death of Shivaji, the founder of the Maratha Empire, the Peshwas emerged as the de facto rulers. They were known for their military prowess and strategic acumen.

Explanation:
After Shivaji, Balaji Baji Rao, also known as Nana Saheb, is widely regarded as the greatest exponent of guerrilla tactics. He was the second Peshwa of the Maratha Empire and served from 1720 to 1740. Balaji Baji Rao's military strategies helped the Marathas in their expansion and consolidation of power.

Guerrilla Tactics:
Guerrilla tactics refer to unconventional warfare strategies that involve small, mobile units using ambushes, hit-and-run tactics, and surprise attacks to harass and weaken the enemy. These tactics often target supply lines, communication networks, and vulnerable points to disrupt the enemy's operations and morale.

Significance of Balaji Baji Rao:
1. Expanding Maratha territories: Balaji Baji Rao successfully implemented guerrilla tactics to expand Maratha territories. His military campaigns resulted in significant victories against the Mughals and other regional powers, which helped the Marathas establish their dominance in central and northern India.

2. Strategic planning: Balaji Baji Rao was known for his meticulous planning and understanding of the terrain. He would carefully select locations for ambushes and surprise attacks, taking advantage of the natural topography to maximize the effectiveness of his forces.

3. Flexibility and adaptability: Balaji Baji Rao's guerrilla tactics allowed the Marathas to adapt to different situations and respond swiftly to changing circumstances. This flexibility helped them counter larger and more conventional armies.

4. Harassment of the enemy: Balaji Baji Rao's forces constantly harassed the enemy through guerrilla warfare. They targeted supply lines, disrupted communication networks, and launched surprise attacks on vulnerable enemy positions. This constant pressure weakened the enemy's morale and ability to effectively counter the Marathas.

5. Defense of Maratha territories: Balaji Baji Rao's guerrilla tactics were not limited to offensive operations. He also employed them for the defense of Maratha territories. By using hit-and-run tactics, he effectively defended against enemy incursions and prevented their encroachment on Maratha lands.

Conclusion:
Balaji Baji Rao, the third Peshwa of the Maratha Empire, is considered the greatest exponent of guerrilla tactics after Shivaji. His strategic acumen, flexibility, and meticulous planning enabled the Marathas to expand their territories and counter larger enemy forces. Balaji Baji Rao's military campaigns and use of guerrilla tactics played a crucial role in establishing the Maratha Empire as a dominant power in India.