Nikumbhilā was a sacred grove inside Laṅkā, the city of Rāvaṇa. It was the yajña-ground where Indrājit, Rāvaṇa’s son, performed his most powerful secret rites. These rites made him unseen and unbeatable in battle. The grove is best known as the place where Lakshmaṇa, led by Vibhīshaṇa, broke Indrājit’s unfinished yajña and slew him. His death took away Rāvaṇa’s last great shield and made the final victory possible.

The grove and its power

Nikumbhilā lay within the bounds of Laṅkā. It was known, and feared, as the place where Indrājit went to draw his most terrible divine powers through secret rites. It had a yajña-vedī (sacrificial altar) made for Indrājit’s use alone. The weapons born from his rites there were of a kind that ordinary means could not meet.

At Nikumbhilā Indrājit had done the rites that let him bind the whole vānara army, and Śrī Rāma and Lakshmaṇa themselves, with his nāgāstra (serpent weapon) in the first phase of the war. The śakti-astra that brought Lakshmaṇa close to death also came from the power of these rites. The Vālmīki Rāmāyaṇa tells of the nāgāstra in Yuddha Kāṇḍa, Chapter 44.

The decisive night

Vibhīshaṇa learned that Indrājit had gone back to Nikumbhilā to perform another such yajña. If it were completed, it would give him complete invincibility for the rest of the war. Vibhīshaṇa told Śrī Rāma at once. He knew the secret: if the yajña was broken off before it was finished, Indrājit’s protective power would not appear, and he could be met and slain. This news was the turning point of the last phase of the war. The Vālmīki Rāmāyaṇa tells this in Yuddha Kāṇḍa, Chapter 80.

Śrī Rāma sent Lakshmaṇa at the head of a great vānara force, with Vibhīshaṇa as guide. Vibhīshaṇa knew every path in Laṅkā and led them to Nikumbhilā under cover of night. When they arrived, Indrājit was in the middle of his rite, with the fire burning and the offerings being made. Vibhīshaṇa gave Lakshmaṇa the signal. The vānara army broke into the grove and disturbed the yajña before it could be completed. The Vālmīki Rāmāyaṇa tells this in Yuddha Kāṇḍa, Chapters 80–85.

Indrājit rose in fury from the unfinished rite and fought the vānara army and Lakshmaṇa in a fierce battle. Without the protection of a completed yajña, and with Lakshmaṇa backed by the cause of Śrī Rāma, Rāvaṇa’s son was at last slain. Lakshmaṇa cut off his head with the Indra-astra. Nikumbhilā, the source of Indrājit’s seemingly endless power, became the place of his death. The Vālmīki Rāmāyaṇa tells this in Yuddha Kāṇḍa, Chapter 90.

In the Tulasī Rāmāyaṇa

The Tulasī Rāmāyaṇa gives the Nikumbhilā episode with the same main events. Indrājit falls back after being stunned in battle and decides to perform the ajaya-yajña (the rite for unbeatable power) in the Nikumbhilā forest. Vibhīshaṇa’s network of informers reports this. Rāma sends Lakshmaṇa with Aṅgada and Hanumān. The vānaras break up the homa (fire offering) in the middle of the rite, and Lakshmaṇa slays Indrājit with a mahāstra (great weapon). This is in the Laṅkā Kāṇḍa, in the section on the slaying of Meghanāda by Lakshmaṇa.

Sources

Vālmīki Rāmāyaṇa, Yuddha Kāṇḍa, Chapters 80–90, and Chapter 44
Tulasī Rāmāyaṇa, Laṅkā Kāṇḍa