Praacheen kaal mein Priyavrat naam ke ek pratapi aur dharm-paraayan raja the. Unki patni Maalini guni aur susheel thi, parantu donon ko ek hi dukh tha — unke koi santaan na thi. Santaan ke abhaav mein raaj-vaibhav bhi unhe soona-soona lagta tha. Maharishi Kashyap ke paraamarsh par raja ne putra-kaameshti yagya karvaaya.
Yagya ke prabhav se rani Maalini garbhwati huin. Poora raaj-paat aanandit ho uthha. Par jab prasav ka samay aaya, to dukh ki baat yeh hui ki rani ne ek mrit (nirjeev) putra ko janm diya. Yeh dekhkar raja-rani par dukhon ka pahaad toot pada. Raja apne us mrit shishu ko godi mein lekar shamashaan ki ore chal pade aur shok mein apne praan tyaag dene ke liye vyaakul ho uthhe.
Usi kshan aakaash mein ek divya, tejomay vimaan prakat hua. Usmein Brahma ji ki maanas-putri Devsena viraajmaan theen, jinhe Shashthi Devi (Chhathi Maiya) kaha jaata hai. Unhone raja se kaha — "He raajan, main srishti ke chhathe ansh se utpann Devsena hoon, aur baalakon ki rakshika hoon. Jo shraddha se meri aur Surya Dev ki upaasna karega, use main santaan-sukh aur uski raksha ka vardaan deti hoon."
Itna kehkar Devi ne apne divya hath se us mrit shishu ko sparsh kiya, aur dekhte hi dekhte bachcha jeevit ho uthha. Raja Priyavrat ka harsh ka thikaana na raha. Devi ke aadesh par usne Kartik maas ke Shukla paksha ki Shashthi ko vidhi-poorvak Surya Dev aur Chhathi Maiya ki aaradhana ki.
Raja ne nadi mein khade hokar doobte (sandhya) Surya ko arghya diya aur agle prabhaat ugte Surya ko arghya dekar vrat sampann kiya. Tabse Chhath ka yeh mahaaparv prachalit hua, jise aaj bhi nahay-khay, kharna (lohanda), sandhya arghya aur ushaa (prataah) arghya — in chaar dinon mein kathor niyam, shuddhata aur shraddha se manaaya jaata hai. Vrati log bina kisi sahaara ke ghaaton par khade hokar Surya ko arghya dete hain.
Seekh: Chhath vrat aatm-shuddhi, sanyam, swachhata aur Surya ki upaasna ka mahaaparv hai. Yeh prakriti (Surya aur jal) ke prati kritagyata sikhata hai aur santaan tatha parivaar ki sukh-samriddhi, aarogya va deerghaayu pradaan karta hai.