I know three nights, 19th, 21st and 23rd are among the nights of Qadr according to the Shia. Why is the 23rd of Ramadan considered more likely and preferred in Shia Islam?
The Prophet (SAWA) and his Holy Progeny Ahlul Bayt (AS) emphasized more on the 23rd night of the month of Ramadan. It is narrated that a Muslim from the tribe of Johaina (Johani) living far away from Madina came to the Prophet asking him: When shall I come to your Masjid in Madina for Laylatul Qadr as I live far away and can not come more than one night? The Prophet replied him as narrated: Come on the 23rd night of the Month of Ramadan. That is why, the 23rd night is called the big night of Qadr and also the night of Al-Johani.
Wassalam.