Our Ambrose is right on track. Fukamushi (deep steaming) is just a way of making a poor or mediocre quality sencha a little more interesting. High quality sencha is never deep steamed, either asamushi (light) or chumushi (medium) steaming methods are used. Some fuka teas can be alright every now and then but most of them are just green swamp water that tastes more like sludge than tea.