This was supposed to be a high-scoring World Cup with the bowlers just making up the numbers, but there has been a much closer contest between bat and ball. And according to one of the men responsible for these low scores, Trent Boult, this might all be down to the glossier Kookaburra balls made available for this tournament.

Unlike with the red ball, it is hard to tell from the outside how shiny the white ball is. The lot for this World Cup is shinier, says Boult, which has helped the fast bowlers swing it more. Kookaburra, however, is of the opinion that any change in the ball is part of its normal evolution, while the ICC says it is happy with the results yielded.

"The ball is actually different for this tournament," Boult said after New Zealand's two-wicket win against Bangladesh in another low-scoring match. "They have got a different gloss on them. Or they are painted differently, so I don't know if you have talked about it too much but there has definitely been a little bit more swing. Where the white balls have been quite prominent in that you can see their quarter seams, and everything with the ball but now it is fully covered. It is nice to hold in the hand. It is moving a little bit. Yeah, we are happy."

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When asked if it was just the ball or the conditions, too, having an impact on the run-scoring, Boult said: "It is hard one. I want to say a lot of it is the ball. But, yeah, conditions have been pretty good all around the world. But I believe there should be a period at the start of play where it is battle of bat versus ball. And it is an even one. It is nice to see the ball moving like it is at the moment."

Boult said the ball for this World Cup felt a bit like the pink ball used in day-night Tests, which has more lacquer on it to help it last a minimum of 80 Test overs. He didn't know, though, if this was a conscious move from the ICC or Kookaburra. "I have no idea why they have done it like that to be honest. The pink ball was like that. With the pink ball, you couldn't see the quarter seam. Whether they have gone with feedback on how the pink ball performed, I am not sure."

The white Kookaburra has been a topic of debate ever since it stopped swinging just after the 2015 World Cup. During that tournament, Boult and Tim Southee hooped it round corners to form an ultra-aggressive New Zealand plan where they bowled long spells at the start of the innings. Ever since then, the white ball has rarely swung conventionally, even for bowlers who will extract every last bit of swing available.

"I can't really remember the ball [used in 2015], to be honest, but I can remember it swinging," Boult said when asked if he saw a big difference between the balls used in 2015 the World Cup and just after. "I don't know. It is just one of those things. It hasn't swung like that in New Zealand ever since. Great feeling and great tournament obviously to be a part of. Hopefully we can replicate some of the scenes from back then to 2019."

It turns out this is not a conscious effort on the part of either the ICC or Kookaburra nor is it an overnight development. It might just be natural evolution. "There's been no directive on changing the white ball for this World Cup, nor anything definitively changed," Kookaburra told ESPNcricinfo. "There is a constant evolution that dates right back to World Series Cricket in 1977 and through to the pink ball for day-night Test cricket, with improved hardness and finish of the ball the key objectives; we research, test and improve, and this is the result."

The ICC confirmed to ESPNcricinfo it has made no specific request to Kookaburra in this regard. The ball manufacturers, though, are quite happy with the results. "We're really pleased with the feedback on the white ball in this World Cup to date. Our aim is to provide balance for swing, seam, spin and the batters, and this positive feedback has been consistent with what we've heard for the last two years around the world. Perhaps that general improvement is just more obvious right now that we're on the global stage at a World Cup but it's not an overnight change; it's [been] years in the making."