Shirts for the hill, the peg and the yard, in the weights that actually get worn.
Tattersall check is the default for a shoot day. Hoggs of Fife carry it through the Inverness, Viscount Premier and Ambassador Premier in cotton weights that take a tie and sit under a tweed jacket without bulk. Jack Pyke's Countryman check does the same job at a lower price, and comes in a ladies' fit. For heavier work, Swanndri's Barn, Bendigo and Paihia shirts are New Zealand patterns that wear more like a light jacket than a shirt.
Where you are moving and sweating, look at ShooterKing's Bamboo shirts and the Deerhunter Atlas instead — softer, quicker to dry, and better next to skin on a warm stalk than cotton.
Two things people get wrong. Buy a shooting shirt with room across the yoke: a shirt that fits standing still will stop you mounting a gun. And check the collar if you wear a tie on driven days — a soft button-down will not sit right under one.
Ladies' and boys' fits are stocked. See also T-Shirts, Women's Hunting & Shooting Clothing and Clothing.
