There are two grades of green tea leaves: one is superior quality ‘Gyokuro’ and other is normal ‘Sencha’ green tea. ‘Gyokuro’ has a darker colour and slightly stronger taste. Originally ‘Gyokuro’ was drunk by aristocrats in Japan as a medicine. Since it is grown and produced with extra care, it is normally quite expensive. It is very rare to be able to get it in tea bag form.