'Ekadasi' is the term for the 11th Moon Phase important to Lord Vishnu.
Jyeshta Ekadasi is the day when the 11th waxing moon coincides on the Jyeshta Nakshatra. Jyeshta is the star ruled by Mercury and Lord Vishnu is the overlord of this planet.
Lord Vishnu, the Sustainer of the Universe, the God of Wealth, suddenly manifested on the lunar day Ekadasi.
This particular 11th Moon is also called 'Hari Sayana Ekadasi' as after performing several miracles in the universe, Lord Vishnu reclines on the cosmic serpent Adi Sesha, and falls asleep in the cosmic Ocean of Milk. 'Hari' is another name for Vishnu and 'Sayana' means sleep.For Your Peace and Happiness
Observing this particular Ekadasi, brings blessings for peace and happiness.
Chant the mantra for Lord Vishnu -- Om Namo Narayanaya