Each World Cup seems to throw up something fresh for which they are remembered.
In 1987, Australia brought us bowling variations such as slower balls, now an integral part of a bowler's armoury, through players like Steve Waugh and Simon O'Donnell; coloured clothing and white balls were introduced in 1992 while Dipak Patel opening with his offspin threw a spanner in opposing teams' plans; the Sri Lankan openers went hell for leather from the start in 1996; while in 1999, with the tournament played in England in May and June, the Duke balls gave the good seamers a field day.
This time I'll be watching for how the better teams handle the introduction of two new balls in each innings. It necessitates smart thinking, by both the batting and bowling groups.
For bowlers it will be about how to utilise your strike weapons to put early pressure on batsmen. Against Pakistan in Wellington recently, Brendon McCullum bowled Kyle Mills' 10 overs straight through for just 29 runs, keeping things tight, and used Trent Boult, Adam Milne and Corey Anderson in shorter spells. By the 36th over Pakistan were 133 for six and on the skids.
For the batting side it's about counteracting the bowlers' skills. On any given day you play on different pitches, so you need to make quick assessments.