How 3-way and 4-way swaps work (and why most sites miss them)
A direct swap needs two people who each want exactly what the other has. That's rare. Chains are how most moves actually happen.
Why direct swaps are rare
A direct swap is a coincidence: you want their home and they want yours. The bigger and pickier the market, the less often that exact double-coincidence happens. Plenty of people sit for months waiting for a direct match that statistically may never come.
What a chain looks like
A chain solves it by closing a loop. Imagine: you want the Okafors' flat in Sheffield, the Okafors want Dani's place in York, and Dani wants your house in Leeds. No two of you are a direct match — but together you form a perfect circle, and all three move at once.
The same idea extends to four, five or more households. As long as the loop closes, everyone gets the home they wanted.
How the matching works
Finding chains by eye is effectively impossible once you have more than a handful of homes. HousingBase uses a method called Top Trading Cycles — the same family of matching algorithms used to arrange kidney-donor chains — to scan everyone's preferences and surface the loops that actually close.
You don't see any of the maths. You just see: here's a three-way swap that works, and here's exactly who moves where.
Why most sites miss them
Older swap sites are essentially searchable lists. They show you homes and leave you to spot a match yourself — which means they only ever really surface direct swaps. Multi-way chains are invisible to a human scrolling listings, so they go unfound, and people who could move don't.
What this means for you
Set what you actually want, not just what you'll accept, and don't dismiss your search because no direct swap exists. The chain that gets you moving may involve people you'd never have thought to contact.