Kyon Nai was an appointed meeting place of the Divine Couple Sri Radha-Krsna. Once, Sri Krsna was waiting for Srimati Radhika here. Some of Srimati Radhika's friends had wanted to test Krsna's eagerness to meet with Her, so they had arrived early, and hidden Srimatiji in a nearby kunja. When He saw the sakhis Krsna asked eagerly, "Kyon na ai? - why has Kisoriji not come?" To increase His longing they answered: "Abhimanyu (Her husband) is home today and Jatila(Her Mother-in-law) and Kutila( Her Sister-in-law) are vigilantly keeping watch. She cannot leave the house, so there is no possibility of Her coming to see you."
This news distressed Krsna and it showed on His face. Pleased to see Him afflicted by separation from Srimatiji, the sakhis brought Her out from the kunja. In this way they arranged Her meeting with Krsna. Since Krsna asked the question Kyon na ai? here, the place was named Kyon Nai (Konai).
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I have read some stories that Radhaji was married to abhimanyu and has jatila as mother-in-law and kutila as sister-in-law. I don't know much detail about their marriage.
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