Why did they break their cups after a toast?


In episode 17 when they're about to welcome Satsuki's mother, they're having a
toast and slam their cups to the ground. Why did they do it? Does this have
anything to do with Japanese culture?

![enter image description here](https://i.stack.imgur.com/sMCin.jpg)




It's from a Russian tradition that went back to Peter the Great and now it's
done after important toasts.

From the [Table-glass Wikipedia
page](https://en.wikipedia.org/w/index.php?title=Faceted_glass&direction=prev&oldid=625044655)
(bold emphasis added):

> A legend says that the first known faceted glass was given as a present to
> Tsar Peter the Great from a glass-maker called Yefim Smolin, living in
> Vladimir Oblast. He boasted to Tsar that his glass couldn’t be broken. Tsar
> Peter liked the present, however, after drinking some alcoholic beverage
> from it, he said loudly _Let the glass be!_ (Russian: Стакану быть! -
> literally _the glass be_ ), **threw the glass on the ground** and managed to
> break it. But Peter didn’t punish the glass-maker, and the production of
> such glasses continued. According to the legend, people present during this
> episode misinterpreted the Tsar’s words and thought that Peter called to
> **break the glasses** (Russian: Стаканы бить! - literally _beat glasses_ or
> _break glasses_ ), that’s how a tradition of breaking drinkware on certain
> occasions appeared in Russia. Glasses were broken after especially important
> toasts or just during the especially cheerful parties. Russian restaurants
> even held a special prices for breaking the glasses. Breaking of drinkware,
> or, in wider context, any tableware, is believed in Russia to bring luck and
> happiness.




It's from a Russian tradition that went back to Peter the Great and now it's
done after important toasts.

From the [Table-glass Wikipedia
page](https://en.wikipedia.org/w/index.php?title=Faceted_glass&direction=prev&oldid=625044655)
(bold emphasis added):

> A legend says that the first known faceted glass was given as a present to
> Tsar Peter the Great from a glass-maker called Yefim Smolin, living in
> Vladimir Oblast. He boasted to Tsar that his glass couldn’t be broken. Tsar
> Peter liked the present, however, after drinking some alcoholic beverage
> from it, he said loudly _Let the glass be!_ (Russian: Стакану быть! -
> literally _the glass be_ ), **threw the glass on the ground** and managed to
> break it. But Peter didn’t punish the glass-maker, and the production of
> such glasses continued. According to the legend, people present during this
> episode misinterpreted the Tsar’s words and thought that Peter called to
> **break the glasses** (Russian: Стаканы бить! - literally _beat glasses_ or
> _break glasses_ ), that’s how a tradition of breaking drinkware on certain
> occasions appeared in Russia. Glasses were broken after especially important
> toasts or just during the especially cheerful parties. Russian restaurants
> even held a special prices for breaking the glasses. Breaking of drinkware,
> or, in wider context, any tableware, is believed in Russia to bring luck and
> happiness.

