WoN Calender

The WoN calendar was established about 800 years before the game start by Shogun Jikan early in his reign. The calender works on a 300 day rotation with 10 months, each 30 days long. There's 5 weeks in each month, and a week is 6 days long. The sixth day equates to our weekend, and it generally a day of rest and relaxation. The calendar is called the Daijikan Ryou (jap. "the Great Time Flow").
Prior to this, time was measured in relation to the ruling Shogun's reign, so each year would generally last several of our years, until a Shogun died or was deposed. This was the system instituted by the Prince of Blades , and was known as the Jidai no Shogun (jap. "Era of the Shoguns").
Prior to that, each village kept their own calendar, though many were forced to take on the calendars of the great villages that controlled them. Samurai too used various different calendars depending on location and and relation to the nearby ninja clans.