England's pace bowlers seized the initiative on day three of the second Test with two more wickets in the first hour as New Zealand stumbled to 125 for five at the Basin Reserve.
In reply to 465 all out, the Kiwis were therefore in obvious danger of following on at some point under forecast cloud cover.
Stuart Broad struck first with a sharp caught-and-bowled to see off Kane Williamson in the fifth over of a still bright morning and four balls later James Anderson got one through the defences of the other overnight batsman Dean Brownlie.
England's first wicket was a bonus breakthrough, achieved in unlikely circumstances. Williamson drove a full-length ball back at the perfect height for Broad to hold the chance just to his left in his follow-through. It was a mode of dismissal which could hardly have been part of the plan.
But as on the second night, when Broad took two in two, England again cashed in quickly - thanks to Anderson this time.
The tourists' pace spearhead had not been as accurate in his first two overs as he was the previous evening, but got one in the right place to Brownlie - who went back and was hit deep in the crease by a delivery which nipped into him.
The height of impact gave him hope on DRS, but simulation narrowly vindicated umpire Asad Rauf's lbw decision.
Broad had already beaten new batsman Brendon McCullum's outside edge first ball and did so again with a very good outswinger three overs later before also snaking one back into the New Zealand captain to hit him on the pad just outside the line of off-stump.
In between, though, McCullum had hit Broad for two back-foot fours through the off-side and then pulled him for a mighty six over square-leg.
His further contribution, or otherwise, to his team's first innings already seemed to be a pivotal factor in the outcome of this match.
