How heavy should a Chinese chef's knife be?

A chinese style chef's knife, also known as the cai dow, or vegetable cleaver(trial subscription required, but an excellent article), is superficially similar to a western cleaver. The cleaver is typically a very robust blade, thick and weighty, meant for separating meat at the joint, splitting ribs and chops, and other tasks that require a lot of weight and a stiff blade.

The chinese chef's knife will be much thinner and lighter, comparable to a western chef's knife or Japanese nakiri. The broad face is for scooping up ingredients from the cutting board and controllability rather than mass and strength. From a brief blog entry from Kitchn on the knife -

In her book Shark’s Fin and Sichuan Pepper: A Sweet-Sour Memoir of Eating in China, Fuchsia Dunlop explains, “The Chinese cleaver is not a butcher’s knife...The everyday cleaver, the cai dao or vegetable knife, is unexpectedly light and dexterous, as suitable for slicing a small shallot as a great hunk of meat, and used by everyone from the most macho chef to the frailest old lady.”

Many actual Chinese cooks use very large cleavers which are heavier than a typical western chefs knife

These are used for everything, meat, veges, noodles, small things, large things, even when doing tricky stuff

Hot pot butchers (usually working on the street outside a restaurant) use very large and slightly curved cleavers to make thin slices of lamb (mutton!), these are about 500 mm long, and look very heavy, but make short work of the animal

All this seems to be mainly cultural, e.g. when you check out some of the fancier restaurants around Shanghai, you will see some of the chefs using typical western chefs knives :-)

Weight and thickness with depend on what you are cutting and personal preference. Many Chinese cleavers are marked with a numbering system, which depends on the manufacturer. A very light one is used for light jobs (mostly vegetables), and medium for all purpose jobs (vegetables and boneless meats) , and the heavy ones for bones just as a Western cleavers.

But in most cases it is going to weigh more than a typical western chef's knife. The typical Chinese cleaver is going to feel much more blade heavy. So getting your grip as close to the blade is going to give you more control and less fatigue, until you get used to the feel of the cleaver. The blade heavy balance helps you use the cleaver's weight to your advantage. Basically just lift the blade and let the weight cut the food, with just a bit of downforce and guidance on your part.