Petty==utility?Now, I'm gonna have to disagree with @JimP42 on something.
Since you want something a little smaller than an 8" chef, here are your usual possibilities :
6" chef
5.5" santoku(7" is close enough to an 8" chef to not be worth considering.
Utility/petty knife
If I were going to get a knife that your wife could use, no question, 5.5" santoku. Women love santokus at that size.
But if I were going to get a smaller, nimble knife for me, I know jimp42 doesn't like them, but I love a petty knife. Has the length to do work like a chef knife, and you can really choke up on it when holding it like a paring knife.
Often times I will stick to just chef and petty knife, and never use a paring.
You do you, but I can’t use those like a chef knife because a proper chef knife grip would extend below the blade edge. Not good. My favorite paring knives are a little 2.5” pointy one and a 2.75” peeling (birds beak) knife. Thumb isn’t used to hold paring knife at all 95% of the time. Completely different usage/leverage/balance/etc… and not very suited to a ~6” utility at all.
I agree on the 5.5” Santoku. That’s the fave of one of my daughters. The other likes the 6” chef’s.