What is a toucher, and how is it marked?

What counts (law 14). A bowl in its original course that touches the jack is a live bowl called a toucher, even if it comes to rest in the ditch within the boundaries of the rink. A bowl that does not touch the jack in its original course is a non-toucher. A bowl is also a toucher if, after coming to rest, it falls and touches the jack before the next bowl is delivered (or, for the last bowl of an end, within the 30 seconds in law 23.1). No bowl becomes a toucher by playing onto or contacting the jack when the jack is in the ditch.

Marking (law 15). A toucher is marked with chalk by a member of the team that delivered it, or by the marker, as soon as it comes to rest. If marking would be likely to move the bowl or alter the head, it is nominated as a toucher instead. If a bowl is neither marked nor nominated before the next delivered bowl comes to rest (or, for the last bowl, before the 30 seconds), it is no longer a toucher. A chalk mark left on a bowl that does not become a toucher is removed by an opponent or the marker.

In the ditch (law 14.4). A toucher in the ditch is marked with a brightly coloured indicator (not more than 50 mm wide and 100 mm high) placed vertically against the face of the bank or on top of the bank in line with the toucher. Lines can also be drawn around it in sand, or with chalk on vegetation or synthetic surfaces.

Source: World Bowls, Laws of the Sport of Bowls Crystal Mark Fourth Edition, laws 14 to 16, https://www.worldbowls.com/wp-content/uploads/2023/05/Laws_of_the_Sport_Fourth_Edition.pdf