Editing D'ni time conversion (section)

== D'ni Timekeeping ==

The essentials of the D'ni timekeeping system were first documented by Cyan Worlds on their [http://web.archive.org/web/20070101161036/www.riven.com/dni_time.html D'ni Time] Web page. This information is also available on the [https://web.archive.org/web/20130523171749/http://drcsite.org/dnifaq.php D'ni FAQ] page of the [[DRC]] web site, and in the [[D'ni time]] article. Some familiarity with base-25 arithmetic and the [[D'ni numerals|D'ni numbering system]] may be helpful in understanding the timekeeping system.

The D'ni equivalents to our year, month, and day are the ''hahr'', ''vailee'', and ''yahr''. The plural forms of the calendar divisions are ''hahrtee'', ''vaileetee'', and ''yahrtee''.

While the D'ni ''hahr'' is approximately the same length as our Gregorian year, they divide it into 10 segments (''vaileetee'') of equal length, unlike our 12 months of differing lengths. In addition, the Cavernian calendar does not require regular corrections equivalent to our leap years, so all ''hahrtee'' are of equal length. This greatly simplifies date calculations in that calendar.

As we further divide our days into hours, minutes, and seconds, so do the D'ni divide their ''yahrtee'' into smaller units. However, they use five divisions: the ''gahrtahvo'', ''pahrtahvo'', ''tahvo'', ''gorahn'', and ''prorahn'' – rather than our three divisions. These divisions are based on the natural cycle of the light-producing algae in the D'ni cavern, and on the D'ni base-25 numbering system.

The D'ni apparently used only the ''pahrtahvotee'' (the D'ni "hour") in casual daily life, numbering them from 1 to 25 on their public clocks, which are known as "''gorahyantee''" in the D'ni language. However, this unit of time was not mentioned in any Cyan or DRC description of the system until March 2007, when a timekeeping brochure was placed in the classrooms of neighborhoods with clocks. The ''pahrtahvo'' was still not mentioned on the DRC web site as of December 2007. Because of this omission, exact times of day are usually given using only the ''gahrtahvo'', ''tahvo'', ''gorahn'', and ''prorahn''. (We do not presently know if this was also the D'ni practice when more precise times were required.) That convention is followed in the remainder of this document, and the ''pahrtahvo'' will not be discussed further.

The D'ni also recognized a larger unit of time – a sort of D'ni century – known as the ''hahrtee fahrah''. This is a span of 100 ''hahrtee'' in base 25 (<dni>100</dni>), or 625 years in surface terms. Dates found in various journals often express the ''hahr'' in a shorthand form relative to the current ''hahrtee fahrah'', much as we might use only the last two digits of the year and omit the century when writing a date. The current ''hahrtee fahrah'' began in 9375 [[DE]], which is written as [15|0|0] in base 25. (This would be the first ''hahr'' of the 16th ''hahrtee fahrah'', because the Cavernian dating system begins with ''hahr'' zero.) Add the shorthand year to the starting year of the ''hahrtee fahrah'' to determine the full year. For example, a date of 101.1.5 in a document would represent Leefo 5, 9476 DE when written in its long form, assuming the document was written in the current ''hahrtee fahrah''.