A total of 8,525,179 voters will decide the political fate of 106 candidates.
"The new electors of 18 and 19 years' age are 388,301. The voting will take place at 10,177 polling stations, of which 2,779 are highly sensitive, 3,070 are sensitive," an Election Commission official told IANS.
For Thursday's polling, 1,946 micro observers have been appointed.
Of the total number of the polling booths, 763 will be covered with video cameras, 1,194 with still cameras and 600 through webcasting.
Around 45,000 security personnel drawn from para-military forces, state police, and home guards have been deployed.
Six choppers will be used, of which two will be for air surveillance.
In the April 17 phase-two voting, the political fate of seven legislators, former central minister and Congress MP from Ranchi Subodh Kant Sahay, deputy speaker of the Lok Sabha and BJP sitting MP Karia Munda, senior BJP leader Yashwant Sinha's son Jayant Sinha will be decided.
The other key candidates are former deputy chief minister and All Jharkhand Students Union president Sudesh Mahto and former IPS official and president of Jharkhand State Cricket Association Amitabh Chaudhary. Both are contesting from Ranchi.