Kane Williamson and Henry Nicholls made double centuries in a 363-run partnership for the third wicket as New Zealand amassed 580-4 before declaring its first innings Saturday on the second day of the second cricket test against Sri Lanka. (More Cricket News)

Williamson posted his sixth double century and was out for 215 and Nicholls brought up his first and highest test score for New Zealand and was 200 not out when captain Tim Southee signaled the declaration.

It was the first time two New Zealand batsmen had scored double centuries in the same innings of a test.

The partnership was the ninth-highest for the third wicket in all tests and New Zealand’s highest since Martin Crowe and Andre Jones made 467 against Sri Lanka in the Basin Reserve in 1991.

Williamson batted for 6-1/2 hours and Henry for one minute longer.

New Zealand resumed on Saturday at 155-2 with Williamson 26 not out and Nicholls and 18. Williamson and Nicholls stayed together for most of the rest of the day.

“It was great fun. The way Kane batted was brilliant and he just allowed me to do my thing,” Nicholls said. “We had ebbs and flows throughout the day but as I said it was a fun day.

“I think we just wanted to bat as long as we can. I think when Kane got 100 he just flew to 130 and we kept feeding off each other. As the day went on we were able to up the tempo a bit and to get those two wickets was great heading into tomorrow.”

At stumps and after 17 overs, Sri Lanka was 26-2 with captain Dimuth Karunaratne 16 not out and nightwatchman Prabath Jayarsuriya 4 not out.

Oshada Fernando was out for 6, caught by Tom Blundell from the bowling of Matt Henry and Kusal Mendis was 4 when he was brilliantly caught at point by Devon Conway off Doug Bracewell who is playing his first test since 2016.

The first day at the Basin Reserve was dark and gloomy. Only 48 overs were possible between the rain-delayed start and finish hastened by bad light. The second day dawned bright and sunny and the pitch at the Basin Reserve, which was soft and slow on the first day, had become firm and ideal for batting.

Williamson scored an unbeaten 121 when New Zealand beat Sri Lanka by two wickets from the final ball of the first test and 132 as New Zealand beat England by one run in the second test at the Basin Reserve one month ago.

Nicholls had gone 10 tests since he last passed 50: he made only 2 and 20 in the first test against Sri Lanka and 70 at 17 in four innings over two tests against England.

Through the day, Williamson and Henry Nicholls built and built and built until New Zealand was in a secure to declare. Milestones passed steadily and at speed.

Kane Williamson reached 50 from 106 balls in 142 minutes and Nicholls’ half century came from 79 balls in 145 minutes as he played a subordinate role early on.

At 91 Williamson pased 8,000 runs in tests and his 28th test century came in 231 minutes with 10 fours and two sixes. Nicholls followed Williamson to a century from 173 balls in just under five hours.

The pair passed 150 for the third wicket, then 200, then 250 and 300 from only 420 balls. Williamson reached 200 from 285 balls, in 460 minutes and the scoring rate picked up as the day went on.

Eventually, it became clear New Zealand was eager to declare and the pace stepped up. Williamson was out for 215, hitting out and caught at long-on. Daryl Mitchell came and went and was out for 17 when New Zealand was 530-4.

Nicholls pressed on and reached his 200 from 249 balls and Southee signaled the declaration soon after from the players’ balcony.