Changes

*The calendar also takes into account the solar year. The solar year is divided into twelve periods by twelve solar points (中気　chûki) : the winter solstice, the spring equinox, the sumer solstice, the autumn solstice, and two points between each. <ref> The year is also divided into 24 "solar terms" (節気 ''sekki'') such as the "Great Cold."  These are the 12 chûki plus the 12 points that are half-way between chûki. </ref> The months are numbered according to the solar point that occurs during that month.  For example, the month in which the winter solstice occurs is the 11th month, and the one in which the spring equinox occurs is the 2nd month.

*The calendar also takes into account the solar year. The solar year is divided into twelve periods by twelve solar points (中気　chûki) : the winter solstice, the spring equinox, the sumer solstice, the autumn solstice, and two points between each. <ref> The year is also divided into 24 "solar terms" (節気 ''sekki'') such as the "Great Cold."  These are the 12 chûki plus the 12 points that are half-way between chûki. </ref> The months are numbered according to the solar point that occurs during that month.  For example, the month in which the winter solstice occurs is the 11th month, and the one in which the spring equinox occurs is the 2nd month.

*Because the lunar month is less than 1/12 of a solar year, sometimes a month falls entirely between the solar points  (中気). <ref>After 1844 the method of calculating the solar points changed, and there could be two in one month. In such cases the designations of the months were arranged so that the month with the winter solstice was the 11th month.</ref> In such cases the month is called an intercalary (閏 uruu) month, and is given the same number as the previous month. For more, see below on '''Intercalary Months'''.

*Because the lunar month is less than 1/12 of a solar year, sometimes a month falls entirely between the solar points  (中気). In such cases the month is called an intercalary (閏 uruu) month, and is given the same number as the previous month. For more, see below on '''Intercalary Months'''.<ref>After 1844 the method of calculating the solar points changed, and there could be two in one month. In Japan in such cases the months with the solstices and equinoxes were given their traditional month numberings, and the numbers of other months were arranged to fit.</ref>

*The first month (New Year) is the month that has the second solar point after the winter solstice. Thus New Year Day is usually the day of the new moon nearest to the first day of spring, about Feb. 4  (see above on the starts of seasons).  In the present Japanese modern lunar calendar, New Years Day is between about Jan. 21 and Feb. 19. <ref> Because both the western calendar and the Japanese calendar have changed in relation to the solar year over time, the possible dates vary with the period. For example, towards the end of the 16th century the new year started between Jan. 24 and Feb. 24.</ref> This means dates towards the end of the Japanese year are in the next year of the Western calendar.  For instance, the death of the [[Twenty-Six Martyrs of Japan]] was 1596/12/19, but it is better known by the Western date of Feb. 5, 1597.  The  [[Ako ronin|Akô rônin]] carried out their revenge on Genroku 15 (1702).12.15, which was Jan. 31, 1703 , so one sees both 1702 and 1703 as the date.

*The first month (New Year) is the month that has the second solar point after the winter solstice. Thus New Year Day is usually the day of the new moon nearest to the first day of spring, about Feb. 4  (see above on the starts of seasons).  In the present Japanese modern lunar calendar, New Years Day is between about Jan. 21 and Feb. 19. <ref> Because both the western calendar and the Japanese calendar have changed in relation to the solar year over time, the possible dates vary with the period. For example, towards the end of the 16th century the new year started between Jan. 24 and Feb. 24.</ref> This means dates towards the end of the Japanese year are in the next year of the Western calendar.  For instance, the death of the [[Twenty-Six Martyrs of Japan]] was 1596/12/19, but it is better known by the Western date of Feb. 5, 1597.  The  [[Ako ronin|Akô rônin]] carried out their revenge on Genroku 15 (1702).12.15, which was Jan. 31, 1703 , so one sees both 1702 and 1703 as the date.

*"Tsuchihashi" and "Zölner" are the authors of two calendrical tables.  For most years they are identical, but in some cases, especially for early years, they are not. To see the problem years use the "database" button and use the link given there.

*"Tsuchihashi" and "Zölner" are the authors of two calendrical tables.  For most years they are identical, but in some cases, especially for early years, they are not. To see the problem years use the "database" button and use the link given there.

*To use the calculator you have to know the nengô of the year.  An explanation of how to do this is found in Japanese eras and the Year dates pages. Or, even easier, run down the list of nengô in the pull-down menu on the calculator until  you find the period your year is in.  The year in the nengo system is [Western year] - [Nengo start year] + 1.    For example, 1600 is in the Keichô period, which started in 1596.  1600 - 1596 + 1 = 5, so 1600 is Keichô 5.  Unfortunately all numbers are in kanji, but you can easily learn the kanji or just count down on the pull-down menu. Note that the intercalary months are preceded by 潤.

*To use the calculator you have to know the nengô of the year.  An explanation of how to do this is found in Japanese eras and the Year dates pages. Or, even easier, run down the list of nengô in the pull-down menu on the calculator until  you find the period your year is in.  The year in the nengo system is [Western year] - [Nengo start year] + 1.    For example, 1600 is in the Keichô period, which started in 1596.  1600 - 1596 + 1 = 5, so 1600 is Keichô 5.  Unfortunately all numbers are in kanji, but you can easily learn the kanji or just count down on the pull-down menu. Note that the intercalary months are preceded by 閏.

*Before entering the month and day, the Western date shown is that of New Year Day of the Japanese year.

*Before entering the month and day, the Western date shown is that of New Year Day of the Japanese year.