5
While we're on the topic of Williamson, the 24-year-old can add to his record of the most centuries by a New Zealand batsman in a calendar year. He has four (v India, the West Indies (2) and Pakistan). Geoff Howarth (1978), John F Reid (1985), Martin Crowe (1987), John Wright (1990), Andrew Jones (1991), Daniel Vettori (2009), Ross Taylor (2012, 2013) and Brendon McCullum (2014) have scored three. Williamson has more centuries (8) in less tests (37) than Glenn Turner (7 in 41), Jones (7 in 39), Howarth (6 in 47) and, dare it be whispered, Bert Sutcliffe (5 in 42). A record tally of 1848 runs across all forms in 2014, overtakes Stephen Fleming's 1658 in 2004.
13
A wicket for Trent Boult in Christchurch would make him the 13th New Zealander to take 100 test wickets. If successful, he will have done it in the third-equal fastest time in 29 tests behind Sir Richard Hadlee (25), Bruce Taylor (27) and equal with Daniel Vettori, Tim Southee and Danny Morrison. The race is also on for New Zealand's highest wicket-taker this year; Boult and Southee have 27 each, and Mark Craig could put in a late run with 25 in his first year.
5
If the test rankings system falls in New Zealand's favour (ie they beat Sri Lanka and Australia defeat India) they could move to fifth by year's end.
Currently seventh, they've consistently stayed ahead of the West Indies this year and are gradually hauling in Sri Lanka and India.
4
This will be the fourth test in the last 16-and-a-half years that Sri Lanka have played without Mahela Jayawardene. The right-hander retired in August after the series against Pakistan, finishing with 11,814 runs at an average of 49.84 in 149 tests. In shades of Bradman, albeit pale shades, had Jayawardene scored 90 rather than 54 in his last innings he would have averaged 50. The three tests he missed were all against Bangladesh (one in 2002 and two in 2013).
13
Taylor has 12 test centuries, placing him level with John Wright on the all-time New Zealand list and behind just Martin Crowe on 17. The upcoming test gives him a chance to claim second place on his own.