What Do the Initials ‘BY’ Signify?

Greetings sake lovers!

I know this is a little sudden, but do you know what the initials ‘BY’ signify? Sakes labelled with these initials and a number, for example, 27BY, is becoming more of a common sight these days. In this article we will explain what it’s all about.

The Meaning of ‘BY’


First of all its not BY as in the word BY, it is B.Y., as in the initials. Unfortunately, in Japan abbreviations tend to come without full stops.

It is not an expiry date.

‘BY’, is an abbreviation of 「Brewing Year」. It basically tells you when the sake was crafted. Nice and easy right? wrong. If it was as easy as all that, there wouldn’t have been a need for this article.

Things get a tad confusing from here on in. Let’s say, for instance, that, as in the above example, the brewing year is marked with the number 27 — now, this is where you need a little bit of an understanding of the Japanese calendar which couldn’t be any more different from the Gregorian one — the 27 will point to the 27th Year of Heisei, or 2015.

So basically, it means that sake was brewed between January and December of that year right?. Wrong. The brewing year points, not to the calendar year, but a predetermined period between specific dates. An industry standard brewing year will normally run from July of one year through to June of the next.

So, in other words, a sake marked as 27BY has been brewed between July 2015 and June 2016. Incidentally, breweries sometimes also write the words ‘Brewing Year’ in full, which in Japanese is written as ‘酒造年度’ (shuzo nendo).

You would be forgiven for wondering why breweries would want to confuse their customers in this way. Well in actual fact the ‘BY’ stamp was never designed to be shown to the consumer in the first place. Originally, its use was restricted to internal auditing purposes. It is not just sake that uses the ‘BY’ stamp: Mirin, shochu, liqueurs and some Japanese fruit wines all get labelled in this way.

Why Show Anything at All?

The ‘BY’ stamp is no longer confined to the back label. Sakes that scream the ‘Brewing Year’ on the front in massive letters, are on the increase. The vintage sake movement may be partly to blame.

Sake is originally intended to be consumed in its freshest state, i.e. immediately; breweries would not dare print anything to create the opposite impression.

Howerer long-term-aged sake has made its entrance — sakes that have, in some cases, been aged for more than a year to produce depth and clarity of flavour — sake that displays a year of vintage in the same way that vintage wines do, and thus, some kind of labelling to set the fresher sakes apart has become necessary. Alas, ‘BY’ is no longer uncommon anymore.

Alternatives to BY

Just when you thought things were confusing enough, they had to go and throw a load of other ‘BY’s into the mix. Here are a few of the more common ones.

BY=Brewery Year’酒造年度’

1st July – 30th June of the next year

CY = Calendar Year

1st January – 31st December of the same year

FY=Fiscal Year

1st April – 31st March of the next year

RY=Rice Year

1st November – 31st October of the next year


And that wraps up another article. and as simple as that, before you can say “BY is short for brewing year”, another sake mystery is cleared up.Why not look out for the BY the next time you are at KURAND SAKE MARKET. Happy imbibing!