Group Bourdon is a page of dot clusters. Your job is to mark every group that has exactly four. Not three. Not five. Four. As many as you can, as cleanly as you can, in a short time.
It looks like something you could do while listening to a podcast. Then the clock starts, and your eyes start to lie.
Why a railway would care about dots
Driving is not dots. Driving is checking the same kinds of thing, again, without drifting. Bourdon is a pure version of that: a dense field, a simple rule, and no story to keep you awake. If you skip rows, invent fours, or speed up until you are guessing, that is useful information to an operator.
The usual failure modes
- Rushing. You mark more groups and also more wrong ones. Speed without a rule is panic with a pen.
- Perfection. You check each cluster three times and finish a third of the page. Too slow is also a fail.
- Losing rhythm. You find a pace, then a hard patch appears, and you never get the pace back.
The skill is a sustainable scan. Left to right, or whatever the instructions say, with a check that is fast enough to be honest. You will miss some. The question is whether you miss like a careful person or like someone who has already left the room.
How to practise
Do timed pages. Not one heroic attempt. Several. Look at two numbers: how much you covered, and how many errors you made. If you only watch one, you will game it.
Practise when you are slightly tired. Assessment day is not a fresh puzzle at 9am. It is one more paper after you have already sat something dull.
Follow the live instructions. Some versions want a mark through the group, some want a box, some are on a screen. The rule is the same. The motor habit should match the day, not your kitchen table.