Understanding the Japanese Imperial Era Calendar

What year is it in the Japanese imperial calendar?

Open your phone clock in Yokohama: it shows 2026. Walk into a city ward office, open a train ticket, or read a shrine’s wooden plaque, and you will see a year like "Reiwa 8". The imperial era calendar counts years from the start of each emperor’s reign. Both systems are legal. Officials and older generations often default to the era name. Visitors who recognise only Gregorian dates can misread expiry dates, booking confirmations, or historical markers.

The current era is Reiwa (令和), which began on 1 May 2019. The previous era was Heisei (平成), which ran from 8 January 1989 to 30 April 2019. Before that came Showa (昭和), from 25 December 1926 to 7 January 1989. Each era name is chosen by the government and announced before the reign starts. Once set, it does not change until the next emperor ascends the throne.

What is the Reiwa era?

Reiwa means "beautiful harmony". Emperor Naruhito acceded on 1 May 2019, making that day Reiwa 1. In the imperial calendar, the first year of an era is always year 1 (gannen), not year 0. Reiwa 1 lasted from 1 May 2019 to 31 December 2019. On 1 January 2020 the calendar ticked over to Reiwa 2.

Because the era began mid-year, the Gregorian and Reiwa years do not align neatly in 2019. From 2020 onward each full Gregorian year corresponds to one Reiwa year:

2026 is Reiwa 8: how to convert

To convert a Reiwa year to Gregorian, add 2018 to the Reiwa number. Reiwa 8 plus 2018 equals 2026. For Heisei years, add 1988. For Showa years, add 1925.

The reverse works too. Gregorian 2026 minus 2018 gives Reiwa 8. Gregorian 2000 minus 1988 gives Heisei 12.

Dates in Japan are often written in big-endian order: year, month, day. "Reiwa 8.4.15" means 15 April 2026. The era name may be written in kanji (令和8年4月15日) or in romanised form (Reiwa 8/4/15). On government forms and some train tickets, the era abbreviation is used: "R8.4.15".

The Heisei era (1989-2019) quick reference

Heisei began on 8 January 1989. Year 1 was shorter than a full calendar year. For the rest of the era, the Gregorian and Heisei years matched except for the first and last years. If you see "H31", that corresponds to 2019, but only from 1 January to 30 April, when Emperor Akihito abdicated. From 1 May 2019 the era switched to Reiwa.

A Heisei date on a building cornerstone, a gravestone, or a document from before May 2019 is simply the Heisei year plus 1988. Heisei 10 is 1998. Heisei 30 is 2018. The abbreviation is "H": H10.1.1 is 1 January 1998.

The Showa era (1926-1989) quick reference

Showa was the longest era in modern Japan, lasting 62 years and 13 days. It began on 25 December 1926 and ended on 7 January 1989. Showa 1 covers only the last seven days of 1926. Showa 64 ran from 1 January 1989 to 7 January 1989.

Showa dates appear in older property records, war memorials, and family registers. Showa year plus 1925 gives the Gregorian year. Showa 20 is 1945. Showa 40 is 1965. The abbreviation is "S": S40.3.21 is 21 March 1965.

Where you'll encounter imperial dates in Yokohama

Yokohama uses imperial dates in several everyday places:

• Train station ticket vending machines at Yokohama Station and Shin-Yokohama Station print expiry dates in Reiwa format on stored-value cards.
• City hall and ward offices (e.g., Naka Ward Office near Kannai) stamp official documents with Reiwa dates.
• Shrines and temples like Iseyama Kotai Jingu or Sankeein Garden use era years on donation boxes and wooden ema plaques.
• Museum labels at the Yokohama Museum of Art or the Cup Noodles Museum often list Showa and Heisei years for exhibits from those periods.
• Pharmacy prescription labels and health insurance cards carry the current Reiwa year.

If you are filling out a hotel registration form in Yokohama and it asks for the year, a quick conversion: 2026 is Reiwa 8. If you write the Gregorian year, the front desk will understand, but they may correct it to the era format.

How era names affect time and date conversions

Imperial dates create a double step for visitors converting times across time zones. First you convert the era year to Gregorian, then you convert JST to your home time. A meeting scheduled for "Reiwa 8.7.15 10:00" is 15 July 2026 at 10:00 JST. That is 15 July 2026 at 01:00 UTC, or 14 July 2026 at 21:00 in New York (EDT, 13 hours behind JST in July).

The same confusion applies to validity periods. A Japan Rail Pass activated on "R8.4.1" is valid for 21 consecutive Gregorian days from 1 April 2026. If you misread "R8" as 2028, you might buy a pass for the wrong year.

Common mistakes visitors make with Japanese dates

• Writing the year first. In Europe and the Americas, dates are usually day-month or month-day. In Japan, the order is year-month-day. "4/15" in the US means 15 April. In Japan, "4/15" usually means 15 April too, but in formal contexts "8/4/15" is 15 April Reiwa 8, not 8 April. Read from left to right: big to small.
• Confusing "R8" with "year 8". Some visitors think "R" stands for a month. It does not. "R" is the standard abbreviation for Reiwa. "H" is Heisei. "S" is Showa. "M" was Meiji. You will see these letters on vending machines, parking tickets, and gym membership cards.
• Assuming the imperial year matches the Gregorian year. This is true only from 2020 to 2026 for Reiwa, and from 1990 to 2018 for Heisei. In transition years (2019, 1989) the two calendars split mid-year.
• Forgetting that year 1 exists. The first year of an era is year 1, not year 0. Reiwa 1 is 2019. Heisei 1 is 1989. This catches spreadsheet users who subtract era numbers directly.
• Ignoring era names on historical articles. A document dated "Showa 20" is not from 1920. It is from 1945. Misreading can cause serious errors in genealogical research or property inheritance.