New Zealand's cricketers have made an art form out ofcontradiction. They can be awesome and awful. They can be dashing and dour. They can slog and stonewall. They can swing it like a million dollars and dob it on a sixpence. They call themselves Kiwis one minute, Black Caps the next. This doesn't mean they're black and white (no, they leave that to their one-day and Test strips). It just means they're no longer the grey men of the international game. New Zealand cricket is colourful these days, and it's hopeless trying to predict what happens next.

An overall diagnosis over the past year confirms that – along with Sri Lanka – they're the most improved side in the world. Yet this assessment is always changing: a caveat here, a concession there. In the VB Series they raised their game against the world champions, winning three out of four matches against Australia … then lost five in a row to extend their paranoid one-day run against South Africa to 14 defeats out of 15. The clean bill of health remains tantalisingly out of reach.

The three wins against the Aussies made it tempting to think that New Zealand were approaching their peak. The same thing happened in 2000 when they stunned the big boys to lift the second mini-World Cup in Kenya. Since then, they have won just a third of their ODIs (13 out of 39). Troughs follow peaks here like sheep follow each other.

Their recent Test form is more consistent, and a drawn series against England would lift them to fourth in the ICC Test Championship. But it's the one-day stuff that matters for the time being, and, for all their Jekyll-and-Hyde tendencies, New Zealand have got enough to win the series. Their key man will be a fast bowler England have never faced. Shane Bond was Man of the Series in Australia and finished with 21 wickets, which was seven more than his nearest rivals, Glenn McGrath and Makhaya Ntini. He has an upright action, genuine pace, bounce that will make Nasser's fingers twitch, and sits alongside Chris Harris, Chris Cairns and, to a lesser extent, Craig McMillan, as one of New Zealand's matchwinners.

The problem is the rest of the seam attack. It's world-class when Cairns and Dion Nash are both fit, but that happens so rarely these days that they sometimes have to trust the canny Harris, the wobbly Nathan Astle, and the bouncy McMillan. As a trio, they're more irritating to batsmen than frightening.

New Zealand's batsmen are often bailed out by the lower-middle order, which is a sign of a good team spirit. Assuming Andre Adams isn't pinch-hitting, they usually have Harris at No. 6, but this is a place too high, even if he is a salvage expert. Lou Vincent has done little since his stunning Test-debut century at Perth, while Astle is just back from injury. This has placed too much onus recently on Stephen Fleming and McMillan, and, when they fail as well, on Cairns, who averaged nearly 45 in Australia and scored at nearly a run a ball.

So just how good are they? Well, it depends on which New Zealand side turns up. The flightless birds, or the Men in Black. It's anyone's guess.

Lawrence Booth is assistant editor of Wisden.com. His reports will appear here throughout England's tour of New Zealand.

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