but it works, so.

WHY????

Just one look and i've already understood what its doing. Kudos.

A portion of that delay is a one-time initialisation delay, rather than a per-iteration delay.

This would solve issues with empties created from splits on pesky spaces, but doesn't handle the scenario where the string ONLY contains a space (which isn't eleminated as a possibility in the brief), which would result in Min failing due to no elements in the sequence.

Assert.AreEqual(0, Kata.FindShort(" "));

This solution is clean and simple, but doesn't take into account if the string, while not empty, contains any number of whitespace that aren't perfectly placed in the string (i.e. whitespace in the beginning or end or double-spaced).

Assert.AreEqual(1, Kata.FindShort(" a"));
Assert.AreEqual(1, Kata.FindShort("a "));
Assert.AreEqual(2, Kata.FindShort("an amp"));

Thanks :D ! I will read about that c:

Func<int,bool> (Func<T,TResult>) is a predefined delegate – a method that has an int parameter and returns a bool. The return type is always the last one in signature and is required for Func<>. And it may be the only type in signature (Func).
In other words, variable is a reference to a value, but delegate is like a reference to a method.
See this: https://docs.microsoft.com/en-us/dotnet/api/system.func-2?view=netframework-4.7.2