Kikkoman started to print Best By Dates on retail supermarket items in the year 2008.
For 2-quart containers or larger, they may still have a production code printed on the container's neck instead. The code is the top (or first set) of printed numbers and letters. The three-digit number before the letters refers to the Day-of-the-Year (like the Ordinal Date or Julian Day Calendar)
, followed by letters that represent the year. All our sauces manufactured in 2021 will have the letters "BA". The letters "BX" were used for 2020, "AW" were used for 2019 and "AT" for 2018. If your Kikkoman product has any other letters, then the product was made over five years ago.
For unopened products in plastic bottles, the soy sauce should be used within two years of its production date code, and, the teriyaki marinade & sauce, rice vinegars, and other Asian sauces generally should be used within 18 months.