What do you use when a recipe calls for thick, dark, light or sweet soy sauce?

I use kikkoman Japanese soy sauce for Japanese recipes, and Tamari (deeper more complex flavor) for all-purpose, but those descriptions sound like he's using chinese soy sauce. In this case, i use Superior Soy for regular and add a little water to it for Lite; and Soy Superior which is the Dark version . Sweet Soy i would ask a vendor which to get.Thick i don't know; i would have thought Thick and Dark were the same.Dpes he not have a glossary of ingredients in the book? have you tried Google searches and wiki?
Barbara Tropp, my Chinese guru, uses regular Kikkoman as her everyday soy sauce(she calls it 'thin'.)she finds chinese soy sauce too salty in general (see The Modern Art of Chinese Cooking, p.567-9

There are many different soy sauces. Sweet soy sauce can be Thai, Indonesian, Japanese etc. Some will say to simply add some sugar, dissolve and you are done. Not so. For example, Japanese is made (if not bought already made) by adding mirin to soy, boiling, then chilling to get a light syrupy consistency.
Indonesian and other southern Asian sweet soy sauces will have additional layers of flavors, like adding cane sugar and anise, etc.
I am fortunate to have an Asian market not far from home...the soy shelves are about 24 feet long !
Best to start a collection of authentic soy sauces if you are doing a lot of Asian cooking - or be satisfied with soy and sugar. Your call.
The different sauces "do" make a difference to the final authentic taste your recipe calls for.

I did find this recipe for making your own sweet soy sauce at home: http://www.fussfreecooking.com/meatless-recipes/make-your-own-kecap-manis-indonesian-sweet-soy-sauce/