The estimation of Northamptonshire and Glamorgan that the pitch at Swansea would be one their spinners could exploit proved accurate on day one, when slow bowlers James Middlebrook and Paul Best took half of the wickets to fall as Glamorgan were bowled out for 252 after choosing to bat first.
Glamorgan scored 140 of their runs in boundaries but only Stewart Walters injected their batting with much longevity, the former Surrey man finishing unbeaten on 81, his highest score so far for his new county.
Glamorgan picked two slow bowlers, Dean Cosker and Robert Croft. Northants, for whom off-spinner Middlebrook finished with four for 63, gave a debut to Best, a 20-year-old slow left-armer on loan from Warwickshire, who celebrated his inclusion by taking the important wicket of Michael Powell. Stephen Peters and Mal Loye then set up a sound platform for Northants by reaching 67 without loss at the close.
Gloucestershire, who began this round 20 points behind Northants in second place, were indebted to Will Gidman's 85 in Cheltenham, where Surrey paceman Yasir Arafat took five for 86.