At some point during a stay in Japan you may be presented with sake served not in the usual cup or glass, but in a small open-top box made of fragrant wood. Or, more intriguingly yet, you may be provided with a glass set inside a wooden box, in which case the sake will be poured so generously that it overflows the glass and spills into the box below.
While this unique form of service certainly ups the fun factor, it does present a challenge: how in the world are you supposed to drink the sake? In this post, we’ll explain why sake is often served this way, especially in izakaya and casual Japanese-style restaurants. We’ll give you the cultural background, of course, but also some pointers on etiquette so you can enjoy your drink without feeling foolish or making a mess.
Table of Contents
What is a masu?
Let’s start with the box, which is called a masu and has a history of over 1,300 years. Originally, it wasn’t used as a cup and with good reason — those straight edges and sharp corners don’t fit well with the human mouth. Rather, the masu developed as a measuring device for foods including soy sauce and uncooked rice.
Masu boxes are made of a soft, fragrant wood called hinoki (Japanese cypress), also a favorite for crafting large-sized bathtubs for luxurious soaks. Today, the city of Ogaki in Gifu Prefecture, a center for the cypress trade, makes roughly 80 percent of all masu, according to Hideyuki Ohashi, president of Ohashi Ryoki Ltd., a company that has been in the masu business for over sixty years.
So how did a wooden box intended as a measuring cup, and in a shape woefully unsuited for drinking, wind up as a sake cup? There are two reasons, Ohashi explains.
First, the cypress wood used in making masu is also used in building Shinto shrines, which is where happy events such as weddings or the birth of a child are traditionally consecrated. As a result, the wood from which masu are made carries positive associations.
The second reason involves word play. The Japanese language has many homophones, which are words that sound the same but have different meanings. To reduce confusion the sound-alike words are written with different characters. But clever word play is prized in Japan, so people often deliberately mix things up, drawing on the identical sounds to create Japanese-style puns and jokes.
And it’s not just in humor that homophones come into play – they can also be the basis for superstitions and lucky associations. When a sports team is heading for a big match, for example, players may bulk up on bowls of Japanese-style pork cutlets over rice, a dish known as katsudon. This is because katsu, meaning “cutlet” sounds exactly the same as the verb that means “to win.”
But let’s get back to the masu, our wooden box, which is written with this character: 枡. But there are other words in Japanese that are pronounced the same way, including one that is written 増す and means “to increase” and another written 益す that means “to fill up.” Because these words can convey a wish for prosperity and plenty, Ohashi explains, the wooden masu cup has come to be seen as auspicious.
Given these positive associations, masu are a “must” on happy occasions such as weddings and store openings when the first toast is made with sake. Typically, this begins with a colorful ceremony called kagami-biraki (鏡開き, literally “opening the mirror”), in which the guests of honor take up mallets and smash open the wooden top of a large cask of sake. The sake within is then served up to guests in new masu cups, often branded with a character or symbol commemorating the event. Guests are welcome to take their cup home as a souvenir.
Why is sake poured until it overflows?
The other situation in which you may encounter sake in a wooden box is at an izakaya or casual Japanese-style restaurant. If you order nihonshū (sake) by the glass rather than in a bottle or flask for the table, your server may bring an empty glass to the table, set it inside a masu, and then pour away from a large bottle into the glass until the sake overflows and spills into the box below.
In a variation, the glass may be set atop a saucer rather than a box to catch the overflow. Either way, this style of serving is called sosogi-koboshi, a noun cobbled together from the verbs “sosogu” (to pour) and “kobosu” (to spill over). Occasionally you see it referred to as “mokkiri sake,” borrowed from a more general term for a single but generous serving.
And either way, you’ve got a dilemma on your hands: What are you meant to do? Are you supposed to first finish off the sake in the glass, and then tip the contents of the underlying vessel into the glass? Or drink the overflow straight from the box or saucer? And it’s not just the question of which do you drink first; how do you even start when the glass is too full to pick up?
To get answers, I paid a call to the Sake Service Institute, an organization in Tokyo that trains and certifies kikisake-shi, which is like a sommelier but for sake instead of wine. Kikisake-shi are qualified to advise on proper storage and handling, as well as food pairings and just about anything else you’d like to know about Japanese rice wine.
I sat down with SSI executive director Haruyuki Hioki, who kindly explained what this overflow style of pouring is all about.
How and why did overflow pouring of sake come about?
There’s no special meaning or long tradition behind sosogi-koboshi, Hioki told me. It first became popular during the immediate post-war period and was originally seen only in the simple drinking joints that sprang up under railway tracks and around stations in working-class neighborhoods during Japan’s period of high-economic growth.
Gradually, and particularly in the last 15 or 20 years, the practice was picked up by a wider range of bars and restaurants, spreading with the increased popularity of enjoying sake chilled (reishū) rather than heated (atsukan and nurukan) or at room temperature.
“Filling a glass until it overflows is a gesture of generosity,” Hioki explained. “It makes the customer feel good because they think they’ve been given something extra.”
Is serving sake in a box popular with customers?
Yet not everyone is pleased to be served this way. Many customers, and particularly women, consider it unhygienic.
“I’ll tell you why I don’t like it: the masu is unclean,” one female blogger wrote. “I could understand if they used a new one every time, but re-using a container made of wood? There’s no way to get those corners clean! And I don’t trust the bottom of the glass. It was just sitting on some shelf, right? Do you really expect me to drink sake that has been in contact with the filthy bottom of a glass? The whole concept is revolting.”
That is not just the ranting of a hygiene freak; the sanitation concern is real, Hioki told me. “There’s no regulation against sosogi-koboshi, at least not yet, but in our courses at SSI we specifically advise against it. There are too many risks.”
And keep in mind, he said, that the masu was never intended for drinking. “Except at celebrations, when a barrel of sake is broken open and guests are presented with a brand new box, the masu shouldn’t be used this way. It’s too hard to drink from a square without spilling.”
How to drink sake served to overflow
So on the point of spilling, just what is the “proper way” way to drink sake served to overflow? “There’s no specific etiquette,” Hioki told me. “This overflow pouring is hardly a refined practice, after all, and you’d never see it in a formal situation. But if I had to offer advice, I’d suggest drinking down the sake in the glass until there’s room to pour the overflow into the glass. Then set the box or saucer aside.”
My own observation, however, is that every drinker tackles the problem differently. I’ve seen people simply pick up the glass, knowing the vessel below will catch any further spills. Others lower their head and take a no-hands sip to bring the level in the glass under control. Some drink the glass down completely before turning to the overflow, while others tip it into the glass as soon as there is space.
And while confirmed barflies will swear you’re supposed to drink from the straight edge of the masu, with the mark facing towards you, I’ve heard others say drinking from the corner is the only way to go.
My conclusion? There’s no need to worry about manners; just have fun and revel in the abundance.
Want to read more about Japanese alcoholic beverages? Check out:
A Guide to Shochu and How to Drink It
What is Chuhai and Why Does Alcohol Content Differ Depending on Flavor?
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Alice Gordenker is a Tokyo-based writer. She started her career in journalism reporting from Washington, DC for food industry trade publications on regulation and legislation. Since relocating to Tokyo more than 20 years ago, Alice has made it her “life work” to provide insight on Japan through various media including newspapers, magazines, television and film.
She is delighted to be an early contributor to Japanese Food Guide, where she can once again focus on great things to eat, and how they are grown or made.