Clay percentage is the only pitch number worth arguing about

How much clay sits in a square explains more about bounce and wear than any amount of squinting at grass cover.

Grass cover is what television shows you and it is close to the least informative thing about a surface. The number that matters is underneath, and nobody puts it on a graphic.

Clay content, roughly the proportion of very fine particles in the soil, determines how a square behaves when it dries. High clay soils shrink hard, bind tightly and produce a dense, springy surface. That is where consistent carry comes from, and it is why certain grounds have a reputation that survives changes of groundsman, changes of curator and forty years of different weather. The soil is the ground's personality. Everything else is a haircut.

Low clay soils, sandier profiles, do not bind the same way. They give you a softer top that absorbs pace, they wear rather than crack, and they tend to go slow and low in a way that makes the fourth innings a grind rather than a lottery. Neither is better. They are different games and they should be treated as such.

The interesting bit is the shrinking. As a high-clay square dries it pulls apart, and the cracks that form are not a defect, they are the mechanism by which a five-day match gets a result. A ball landing on a crack does something unpredictable. A ball landing next to one behaves normally. That variance rises through a match, which is exactly the shape a long contest wants.

So my complaint is about how boards import solutions. There has been a fashion for shipping in soil, or for building squares to a specification meant to guarantee good cricket, and the result is a slow drift towards uniformity. If every square in a country is built to the same clay range, you have industrialised the one thing that made touring hard and made away wins mean something.

I would rather have a badly behaved square with character than a perfectly specified one that produces four flat draws. Not a popular position with the people selling tickets for day five, I accept.

Ask a curator about his clay percentage and he will tell you the number without hesitating, because it is the one thing he cannot change without digging up the square. Ask a pundit and you get the weather again.