Forget a special cup. Enjoy sake with wine glasses!
You may think that you need a special cup to drink sake.. Actually it's not necessary! Well, a brew-master uses Janomeno kikijoko which is a traditional sake cup with blue and white lines to check color tone of the sake. However, the International Standards Organisation (ISO) defines glasses for tasting wine, stemmed glasses with elongated tapered bowls, and these glassed are applicable to sake too. Same as wine, sake also has recommended glasses depending on its characteristic and SSI (Sake Service Institution) recommends as follows:
Then why is sake served in a special cup and a bottle at a Japanese restaurant? This is based on our culture. It's said that people already used Ochoshi, a kettle made from wodden or metal to drink sake during Heian period (794-1185). People used an Ochoshi with a single spout at a court and the one with double spouts at a casual drink occassion. An Ochoshi with a single spout is still used for a traditional ceremony in Japan.
The special cups and a bottle you may see at a Japanese restaurant are called Ochoko and Tokkuri and appeared in the middle of Edo period (1603-1868). People already used a big Tokkuri bottle to keep liquid, not only sake but also soy sauce and so on because it was believed that its shape prevends liquids from changing taste and flavour. They transferred sake from it to a small ceramic bottle, called Heiji when they enjoyed sake. Heiji is a sake bottle used to dedicate to God and people started to use this ceramic bottle to drink sake too, but its spout is too small to pour quickly and they invented a small Tokkuri which is good size to be on a table. There are variety of design and materials of Tokkuri these days, but it is originally a ceramic bottle without a handle and it was convenient for those who started to enjoy hot sake during Edo period and it got popular. Tokkuri and Ochoko were used at home in general and they were enough size for people to enjoy with their family. Then now they are used at a Japanese restaurant to feel how Japanese have enjoyed sake so far!