The epic Mahabharata war was inevitable. The huge armies were being prepared for the war. Seniors took their decisions about the sides that they would take in the war.
The evil minded Duryodhana who was the prime cause behind the catastrophic war, had a meeting with Dronacharya, Bheeshma, Karna and with other seniors. As Duryodhana wanted to do everything possible to win the war that was based on his greed, he looked into all factors that would help him achieve his goal. He asked his teacher Dronacharya for an auspicious day and time to perform a Durga Puja and to begin the war.
Dronacharya asked Duryodhana to contact Sahadeva who was the twin brother of Nakula and the youngest of the Pandavas. He said that Sahadeva was an astrologer and that he would be the right person to consult. Duryodhana was surprised and he asked Dronacharya how he could ask his enemy for an auspicious date for him to perform a Durga Puja to win the war.
Dronacharya said that Sahadeva would never refuse if Duryodhana approached him just after Sahadeva’s bath and morning Puja. The teacher also told Duryodhana that Sahadeva spoke the truth always and that Duryodhana could trust everything that Sahadeva said.
The following morning, Duryodhana went to meet Sahadeva just after the latter had finished his Puja. He said to Sahadeva although they were foes, he trusted Sahadeva to be a man of Dharma and that he would perform his duty as an astrologer by speaking the truth. Duryodhana asked Sahadeva to consult the almanac and specify the right time to start the war in order to ensure victory for the Kauravas.
Sahadeva readily looked into the almanac, made some calculations and gave his predictions to Duryodhana. He said that the following Amavaasya (New Moon) which fell two days later, was an auspicious time to perform the Durga Puja and to commence the war, as that would guarantee Duryodhana victory. Duryodhana was very pleased and after thanking Sahadeva, he returned to his own army command centre.
Bhagavan Krishna, who knows everything, obviously heard this conversation too and He was upset with Sahadeva for aiding the enemy. Sahadeva defended himself by saying that he had to help anyone who came to him after his morning Puja and that his Dharma prevented him from giving wrong advice to others.
Bhagavan Krishna walked away in a pensive mood as He was trying to think of something to circumvent the serious problem caused by Sahadeva’s advice to the enemy. Duryodhana was sure to win if he started the war on Amavaasya.
He went to the camp of the Pandavas and informed them of Sahadeva’s advice to the enemy. This shocked Yudhishtra, Arjuna , Bheema and even Nakula but they were not particularly upset with Sahadeva. They very well knew about Duryodhana’s treacherous qualities and Sahadeva’s character of being true to his Jyotish Shastra or knowledge of Astrology.
The Pandavas, however, were sure that Bhagavan Krishna would come up with a brilliant solution to the grave problem that they were in. After a while, Bhagavan Krishna smiled and with a twinkle in His eyes, said that He had thought of something. Bhagavan asked Yudhishtra, Arjuna, Bheema and Nakula to not reveal His plan to Sahadeva.
The following morning, Bhagavan Krishna, led the Pandavas apart from Sahadeva, to the riverside in order to perform Tarpanam or oblations to their forefathers. Yudhishtra was surprised and asked Bhagavan Krishna why they He wanted them to perform the ritual a day before Amavaasya or New Moon. Bhagavan asked the Pandavas to trust Him and to follow His commands.
The Pandavas started performing the Tarpanam for their father and ancestors and this perplexed the deities in Heaven. The deities discussed among themselves trying to figure what was going on earth.
The two main deities involved in an Amavaasya, namely Surya Bhagavan and Chandra Bhagavan, rushed to Bhagavan Krishna to ask Him what was happening.
They asked Bhagavan why the Pandavas were performing Tarpanam when it was not Amavaasya. Bhagavan Krishna, again with a twinkle in His eyes, said that it certainly wasn’t Amavaasya before Surya Bhagavan and Chandra Bhagavan appeared before Him to ask him that question. But since the two appeared together with each other before Him, they were conjunct and it was Amavaasya!
Amavaasya was declared and the war was started.
Bhagavan Krishna cleverly ensured that Sahadeva did not go against his Dharma of being an honest astrologer and yet started the war at a time that was inauspicious for the Kauravas!
The Bodhaayana Amavasya is an extra new Moon that occurs on Chaturdashi or a day before the actual New Moon.