Most armours of the Sengoku Jidai, which is what most in the west are familiar with when they consider "samurai" armour, were, in terms of classification, near impossible to place under a single heading. Some of the lacquered materials used wouldn't really have a straight counterpart in standard NWN descriptions anyway.
"Leather" can be anything between what your jacket is made of to hardened, lacquered plate which, if well made, can provide significant protection, so it's a pretty vague term and might therefore be the best. Ashigaru soldiers had cloth, for the most part, usually with only a cuirass and greaves (to use western terms) of lacquered leather or such...
In terms of classifying it in a NWN Module, it's just a practical choice, as Magical Master noted, based on what you want the armour to do and be. In other words, forget the exact materials and think "heavy" or "light" and work from there. (As opposed to cumbersome, medieval full-plate armour of the kind that requires a knight to be winched onto his long-suffering steed because he can't move worth a damn, then I'd see Japanese armours, even the strongest and most ornate, as definitely being light).
That's without querying whether it might be Arcane Samurai Armour with all manner of ethereal attributes which will again alter its categorization and probably make it go a silly colour.
(In my own Modules, I tend to classify all armours and weapons more by the place and culture of origin than the type - Eg:- Pretty much all Aradanth armour is chainmail though styles and types vary considerably. If you're introducing samurai-type armour for a certain race, city or whatever in a Module, you could try simply classifying it by those criteria; players may then wish to collect matching armour and weapons for that culture if they choose to side with them or just like their style, etc).
PS:- To answer your specific question specifically, using the specific three words you specifically gave, then I'd call samurai armour "banded".
Modifié par PLUSH HYENA of DOOM, 07 décembre 2013 - 12:26 .