The Ekadasi that occurs during the dark part of the month of Karttika is called Ramaa Ekadasi. It is most auspicious, for it at once eradicates the greatest sins and awards one the passage to the spiritual abode.
“Anyone who observes sacred Ekadasi during both the light and the dark fortnight of each month is undoubtedly freed from the reactions to the sin of killing a brahmin. One should not differentiate between the Ekadasis of the light and dark parts of the month. As we have seen, both can award pleasure in this world and liberate even the most sinful and fallen souls. Just as black cows and white cows give equally good quality milk. So the Ekadasis of the dark fortnight (Krishna paksha) and the light fortnight (shukla or Gaura paksha) award the same high degree of merit and eventually liberate one from the repeated cycle of birth and death.