Five or six words is a huge amount of entropy. In reality there are other rules in my example than just using words. It starts with a capital letter and includes a conjugated verb (running) both of which increase complexity considerably. And it of a random length, having taken its length from my selection of words rather than from any fixed policy. Few services accept random lengths but imho all should.
There is a great scene in DoctorWho where a door password is a series of concepts (spoken mentally) that one thinks about in a particular order. Fiction, but the person writing that scene knew a thing or two about password complexity.
> It starts with a capital letter and includes a conjugated verb (running) both of which increase complexity considerably.
They reduce complexity: It reduces the number of possibilities on the first character, and the attacker knows that one word must be a (conjugated? present participle?) verb yet, when otherwise it could be anything.
That might not be true for an enemy who has access to some of your other passwords already, but assuming it is I still don't see how the strategy above increases complexity. At best, the complexity remains the same.
There is a great scene in DoctorWho where a door password is a series of concepts (spoken mentally) that one thinks about in a particular order. Fiction, but the person writing that scene knew a thing or two about password complexity.