YAOSC (Yet Another Old School Clone)
The basic element of combat is a “to-hit” roll; this is almost always an opposed roll against a target’s defense. Each attack type (ranged weapons, light hand-held weapons, etc.) gives a bonus to the base 2d10. It is recommended that you calculate in advance your normal to-hit formula for each weapon you carry and unarmed combat style you are trained in, and record it on your character sheet for easy reference when needed.
The formula for a to-hit roll is:
2d10 + [weapon bonus] + [relevant ability modifier (positive or negative)] + [other modifiers]