Japan has it's own annual cycle, and getting in sync with it is essential for anyone living in Japan or interacting with people in Japan. Here are some of the important days, but there are also many annual festivals and celebrations.
Jan 1 New Year's Day (Shogatsu / Gantan) The New Year period (Shogatsu) is considered to last until the 3rd, and many businesses re-open on the 4th or 5th. Jan 2-3 are official holidays for bank and government employees only.
Jan 1 Coming of Age Day (Seijin-no-hi)
Feb 11 National Foundation Day (Kenkoku-kinen-no-hi)
Mar 21 Spring Equinox (Shunbun-no-hi)
Apr 1 New Fiscal Year begins / New Corporate Hires start / School Year begins
Apr 29 Showa Day (Showa-no-hi) renamed Emperor Hirohito Day. Beginning of Golden Week (?gon Sh?kan) which covers a period of four national holidays and the days in between. This is generally not a good time to plan to do business in Japan as many offices close for about 7 to 10 days, depending on the calendar. Many people travel around the country or abroad, so tourist attractions, airports and train stations are crowded and it is hard to get reservations for accommodations and transportation during this time.
May 3 Constitution Memorial Day (Kenpou-kinen-bi)
May 4 Holiday for a Nation (Kokumin-no-kyujitsu) and Geenery Day (Midori-no-hi)#1 / Greenery Day#2
May 5 Children's Day (Kodomo-no-hi)
Jul 18 Marine Day (Umi-no-hi)
Mid Aug (9-17) Festival of Souls (Obon) or Festival of the Dead In some parts of Japan and Tokyo Obon is celebrated in Mid July but the majority of the Japanese celebrate it in mid-August. Although not an official holiday, many government offices are closed. Numerous companies give employees a week's holiday, making the conducting of business difficult due to personnel absences. All modes of transportation are heavily booked at this time making any travel difficult.
Aug 11 Mountain Day / Mountain Day#2
Sept 19 Respect for the Aged Day (Keirou-no-hi)
Sept 22 Autumnal Equinox Day
Oct 10 Health and Sports Day (Taiku-no-hi)
Nov 3 National Culture Day (Bunka-no-hi)
Nov 23 Labor Thanksgiving Day (Kinrou-kansha-no-hi)
Dec 23 Emperor's Birthday
Dec 31 Bank Holiday
Japan's New Years Customs and Greetings
by Diana Rowland, author Japanese Business: Rules of Engagement
