Eighth phase of polling: In Bihar, it's Lalu vs the BJP

Patna: Bihar chief minister Nitish Kumar's struggle in these general elections is nowhere as evident as in the seven constituencies in the state that vote today. (Elections 2014: Track LIVE updates)

His Janata Dal (United) had won four of these seats in north and central Bihar, and its then partner, BJP had won one in 2009. That year, Lalu Prasad Yadav's Rashtriya Janata Dal was washed out, as was the Congress. Of the measly four seats that Lalu's party had won, two - Saran and Maharajganj - were among those that vote today.

This year, one partnership has come undone, another has been restitched and those new equations are expected to have a telling impact in these elections. (RJD bouncing back but Lalu remains grounded)

As in the rest of the state, the main contest in these seven constituencies is between the BJP-led alliance and the RJD-Congress alliance, with the JD(U) expected to be eased out the frame. (Top 10 Contests in the Penultimate Phase of Election)

The BJP is banking heavily on the what it calls the "Narendra Modi wave." (Blog: In Bihar, a Hunger to See Narendra Modi)

The divorce that he forced with the BJP last year is expected to cost Nitish Kumar dearly. (He broke a 17-year-old alliance over Narendra Modi)

The Upper Castes are seen to have shifted their allegiance to the BJP. So, reportedly have the Extremely Backward Castes, or the EBCs, who were so assiduously wooed by Mr Kumar's JD(U). The EBCs see Mr Modi as one of them, and by voting for the BJP, they feel they would have played a role in installing their man as the country's prime minister. (India on Course for Record General Election Turnout)

The Yadavs, who form the core constituency of the RJD are fewer in number in these seven constituencies. So are Muslims. The EBCs have a significant presence. (Elections: Full Coverage)

Lalu's wife Rabri Devi, a former chief minister like her husband, is battling it out with BJP general secretary Rajiv Pratap Rudy in Saran.The constituency had been won by Lalu Prasad in 2009, but he was forced to bow out of electoral politics last year after being convicted for five years by a Ranchi court in a fodder scam case.

He cannot contest himself, but Mr Yadav, buoyed by reports of the Muslim-Yadav (MY) consolidation behind the RJD, has launched an intensive campaign to retrieve lost ground for his party. But his efforts to emerge as the principal political player in the state are being blocked by a galvanised BJP.