Cook closing in on record
Alastair Cook and Nick Compton enjoyed their second century opening stand as England begin their reply well in the third Test against India.
Cook (80no) and Compton were in no hurry as they sought to ensure England's hard-earned advantage was retained after bowling India out for 316 at Eden Gardens.
The captain and his apprentice needed a little fortune to go with their skill, against pace and spin, to reach tea on 121 without loss.
Cook was dropped on 17 when he edged Zaheer Khan low to slip, where Cheteshwar Pujara could not hold the catch.
Otherwise, though, the most likely mode of dismissal appeared to be a run-out as England's openers took chances with scampered singles and more than once were in danger of mid-wicket collisions as they kept taking the same line.
Cook, on the back of hundreds in each of the first two Tests, is in rich form even by his often prolific standards - and his 87-ball 50 contained a memorable straight six off Ravichandran Ashwin as well as nine fours.
Compton had fewer obvious scoring options but also profited from using his feet, hitting Pragyan Ojha for a six of his own over long-on.
By the end of the session, history was beckoning for Cook in the shape of a 23rd Test century which would put him out on his own at the top of a list of great names as the scorer of the most ever for his country.
Compton, on 41, had a maiden Test 50 in his sights.
Monty Panesar had earlier finished with four for 90, to add to his 11 wickets in the series-levelling win in Mumbai, as England picked up the last three Indian wickets for 43 runs this morning - despite some late belligerence from Mahendra Singh Dhoni (52).
Dhoni made his intent clear immediately, up the wicket to the second ball of the day to crunch James Anderson past mid-off.
His overnight partner Zaheer was dropped by Graeme Swann off Anderson, but was soon gone anyway - lbw to a Panesar arm ball.
Panesar also made short work of Ishant Sharma, but the last-wicket pair frustrated England for more than half an hour.
Ojha made no runs, but kept out 19 balls, allowing Dhoni to club Panesar for successive sixes over long-off and long-on as England brought the field up for the final two deliveries of one over.
The cat-and-mouse continued, with four consecutive maidens at one point, and until Cook had to rest Anderson for Steven Finn.
It was a change which brought Dhoni's 50, with his fifth four from 113 balls crashed past cover, but then the end too when the India captain gloved Finn and Swann did well to make ground from slip to complete a diving catch.