Writing Poetry with Constraints: The Poetry of Constraint

Twice a day, for two hours either side of high water, the gates of Silloth's dock swing open. For the rest of the day, no ship can safely enter at all. I've come to think that this little harbour on the Solway is one of the best working metaphors I know for something every poet eventually has to reckon with: the difference between freedom and formlessness. The surprising truth is that constraint, properly understood, is not the enemy of good work. It is often the very thing that makes good work possible.

The Nature of Constraints in Poetry

Here is the instinct almost every young poet starts with when writing poetry with constraints, and I had it myself: that form is a cage. Rhyme, metre, the fixed shape of a sonnet, and the strict architecture of a villanelle all feel like rules imposed on something that should, by rights, be free. The thinking goes that the truest expression is the one with no walls at all—pure free verse, unshaped and unconstrained, following thought wherever it wants to go. There is real poetry to be found that way, without question. However, I want to make the case this week that this instinct, however natural, gets the relationship backwards.

A ship that could enter Silloth's harbour whenever it liked would not be free. It would run aground on the mudflats, because the flats do not care what the ship wants. It is precisely the two-hour window—the constraint—that makes safe passage possible. Take the constraint away, and you don't get more freedom; you get a wrecked ship.

Writing Poetry with Constraints: How Form Becomes a Harbour

Poetic form works exactly the same way. I think it's worth saying plainly to anyone working on their own poems. A sonnet's fourteen lines are not there to trap the poem. They are there to force a kind of pressure and precision that endless space would never produce. When you know you have only fourteen lines, a fixed rhyme scheme, and a turn—the volta—that has to arrive at line nine, you stop reaching for the easy, diffuse gesture. You start hunting for the one exact word that will do three jobs at once: carry the meaning, complete the rhyme, and land the metre. That hunt is where the best lines in the language have almost always come from. Not from unlimited freedom, but from a gate that only opens for two hours and the discipline of being ready when it does.

You heard this principle at work before I ever named it. Longfellow's tide poem is built from an unvarying five-line stanza and a refrain that never departs from itself, stanza after stanza. He did not need a looser form to say something true about an indifferent sea. He needed a tighter one—a poem shaped like the very rhythm it was describing. Its structure rises and falls exactly as the tide does. The constraint was not fighting his subject; it was serving it, just as Silloth's dock gates serve the harbour rather than obstructing it.

The Deadline as a Dock Gate

This principle isn't only true of metre and rhyme. It’s true of every deadline you have ever dreaded. Some episodes ago, we spoke about submitting to literary journals and the long, patient waiting that submission demands. But I want to return to one detail of that conversation now from a different angle. A submission deadline is a dock gate. It is not an arbitrary obstacle placed between you and publication. It is the narrow window that forces the poem to finish. Left entirely to your own timing, with no gate ever closing, a poem can sit half-revised for years, endlessly almost-ready, much like a ship with an infinitely patient harbour that might simply never bother to come in. The deadline's cruelty is also its gift. It makes you decide. It makes the poem dock.

Embracing Constraints in Your Writing

I think this is worth sitting with because it changes how you might approach the next constrained thing that lands in front of you. Whether it's a competition with a strict word count, a form you've never attempted, or a request for a poem in exactly twelve lines, the temptation is to feel hemmed in. You might feel resentful of the limit, as though your real poem exists somewhere just beyond the boundary and the form is keeping you from it. I would gently suggest the opposite is usually true. The boundary is where the real poem is hiding. Somewhere inside that narrow, unforgiving window—the fourteen lines, the strict metre, the two hours either side of high water—is a precision you would never have found if you had been given the whole tide to work with.

Finding Freedom Within Constraints

There is a deeper, quieter comfort in this too, one that connects back to everything the last few episodes have been circling. We have spent recent weeks in places that had lost their purpose entirely, and in a poem about a man who could not work because his hope had no object left to reach for. Silloth offers something gentler: purpose that survives, not because the sea was ever tamed, but because the town learned its rhythm so completely that working inside it became, in the end, indistinguishable from freedom. That is what real mastery looks like. It is not the absence of limits. It is the wisdom to know exactly when the gate is open—and the readiness, built through years of paying close attention, to be there when it is.

So if you take one thing from this discussion into your own writing this week, let it be this: the next time a form feels like a cage, ask whether it might instead be a harbour. Ask what precision it might be quietly offering you, the way Silloth's two-hour window offers safe passage to ships that would otherwise founder on the flats. Mastery is not control. It is knowing exactly when to open the gate—and trusting that the water, rising and falling exactly as it always has, will carry you through if you are ready when it does.

A Practical Exercise

Try this before next week. Take a feeling you've been circling in loose free verse—something that keeps sprawling past the edges of the page—and pour it into a form that will not let it sprawl: a strict sonnet, a villanelle, or even just a single stanza of exactly eight lines in a rhyme scheme you choose in advance and refuse to abandon. Don't aim for a masterpiece. Aim only to notice what the walls do. Watch where the gate forces you to cut, to compress, to find the one word that carries three meanings at once. Then read the free-verse draft and the shaped one side by side, and ask yourself, honestly, which one says the truer thing. More often than you'd expect, it is the poem that had somewhere it was not allowed to go.

If you'd like to keep exploring these ideas of form and constraint, consider ordering Somerset In Verse - Exmoor To Levels In Poetry, available now on Amazon from 3rd September 2026. No pre-orders.