Can I name the commitment that ends my beginning and the sequence that starts my ending, and say what share of the book lies between them?
Is there a turn near the centre, and can I say whether it changes the goal, the protagonist’s knowledge, their mode or their fortune?
Does the first half’s question get answered, or visibly carried, at the turn?
Sequences
Written as a value-shift log, does any sequence repeat its neighbour’s shift at the same stakes?
Could any two sequences of the middle change places without loss, and if so, what links them other than a constant?
If I delete the weakest sequence, does the ending lose anything I can name?
Forces
Does the opposing force act in every quarter of the middle, on the page or through a consequence?
Is there a clock, does the protagonist know it, and does it shorten?
Does at least one event narrow more than one line of action?
The reader
Is the protagonist’s option list shorter at the midpoint than after the beginning, and shorter again at the start of the ending?
Is the question a reader carries at 60 per cent different from the one at 40 per cent?
Is there any stretch longer than about a sixth of the book in which nothing closes?
Exercises
The value-shift log. Write one line for each sequence of your middle with its position as a percentage, then the shift in two parallel sentences and the stakes in a word. Mark every neighbouring pair that repeats both. For each pair, keep the stronger and cut the other, or rewrite the second so that it closes a move the first left open.
The option list. List your protagonist’s open moves towards the goal at four points: after the beginning, at the midpoint, at three-quarters, and at the start of the ending. Beside each move that disappears, give the page that closes it. Where nothing disappears between two points, write the event that would close a move using only material already in the book.
The shuffle. Write each sequence of the middle on a card, shuffle them, and a week later, or with another reader, try to put them back in order. Wherever the order cannot be recovered from the cards alone, a causal link is missing.
The opposition’s calendar. Write the opposing force’s own timeline through the middle, off the page and dated, as though it were the protagonist. Mark each point at which it surfaces in the book as a consequence, and add one wherever a quarter of the middle has none.
Two midpoints. Write two alternative midpoints for your book, a page each: one that changes the protagonist’s goal and one that changes what they know. For each, rewrite the option list for the second half, and keep the version whose list narrows furthest by the start of the ending.