Michael Klinger and Alex Gidman scored centuries for Gloucestershire on a rain-shortened third day against Glamorgan at Bristol.
Klinger (142), Gidman (113) and Dan Housego (82) guided Gloucestershire from an overnight 179-1 to 456-4, in reply to the Welsh county's 448.
But 21 overs were lost to two rain breaks and it is hard to see the game finishing in anything but a draw on such a placid pitch.
Michael Hogan, James Allenby and Dean Cosker each took a wicket for Glamorgan, whose bowling options were limited by the absence of John Glover due to a dislocated finger.
Just when it looked as if Housego would advance to his second century of the summer, he hooked a ball from Hogan to Murray Goodwin, who ran in 10 yards from the square leg boundary to take the catch . His 197-ball innings had contained 11 fours.
The post-lunch scoring had been dominated by Gidman, who continued his good run of form with a 73-ball half-century, which included five fours and a six.
The third-wicket partnership between Klinger and Gidman had realised 132 runs in 33 overs when the Gloucestershire captain was caught behind by Mark Wallace off Allenby, having struck 14 fours and three sixes in a 345-ball innings which lasted seven-and-a-half hours.
Gidman's second century of the season arrived soon after when he flicked Hogan for a single to long leg. The county's former skipper had required just 117 balls to reach three figures, finding 10 fours and two sixes.
Gidman drove Cosker for the third maximum of his innings, but the left-arm spinner had his revenge next ball when he took a low return catch.
After a second rain delay, Hamish Marshall and Benny Howell guided Gloucestershire past Glamorgan's total and quick runs will be needed in the morning if the hosts are to put the Welsh county under any pressure.