Tokkuri or Tokuri is a thin-necked bottle rounded at the bottom. It is now mainly used for pouring sake.
They have a variety of other shapes, including that of a spouted serving bowl .
Traditionally, heated sake is often warmed by placing the sake-filled tokkuri in a pan of hot water, and thus the narrowed neck would prevent the heat from escaping.
They used in more authentic places such as ODEN BARS and RYOTEI In Japan.
And it's so populer for souvenier.