His century was also part of a 249-run fourth wicket partnership which became a Yorkshire record.
The 10th wicket partnership was worth 152 and Alletson scored 142 of these runs.
(The only higher last wicket partnership was between numbers 4 and 11.)
They took the score to 226 with a seventh wicket partnership of 134.
He ended with a hard-hitting 77 not out, after a final wicket partnership of 98 in 102 minutes.
His innings had included 22 boundaries and ended a second wicket partnership that yielded exactly 100 runs.
This stand turned out to be the best eighth wicket partnership in the whole of the competition.
This turned out to be the best seventh wicket partnership of the whole competition.
At the time of writing, this remains a first-class sixth wicket partnership.
The pair seemed to enjoy each other's company, and once again built a solid 4th wicket partnership, batting throughout the remainder of the first day.
