I have a fascination with various aspects of the Judaic calendar. One aspect I find fascinating is kvi'ot.

A kvi'ah is a 3 letter mnemonic (in some cases, a 2-letter mnemonic is used) to indicate the day of the week Rosh Hashannah starts, the type of year, and the day of week for 1st day of Passover. See this for a somewhat more detailed explanation.)

I notice that some kvi'ot are quite rare. Offhand, it seems that the 7 chaser kvi'ah is the rarest (or close to it). This kvi'a causes the 1st day of Chanukah to fall on Friday. It looks like the next time this will occur is in 5784 (Gregorian 2023). I can't recall the last time this kevi'ah occurred.

Rather than manually scanning a historical calendar or typing in trial & error years into Hebcal to see if there's a match, I'm wondering if there is some online program or some way that I can develop a program that will provide a list of specific kevi'ah occurrences. For example, I'd like to input the kevi'ah and a number representing the number of occurrences or perhaps, input a start and end year range.

Is there anything like this, around, or can any "tecchie" out there provide pseudo code or an alogorithm?

  • 1
    How about the chart in the Tur? – Double AA Dec 19 '16 at 21:03
  • @DoubleAA I saw this a while ago. Ideally, I'd like something online. If you can provide a link to this chart, I'd appreciate it. It's been a while since I viewed it. I'd need to view it again to see if this will really do the job. – DanF Dec 19 '16 at 21:08
  • 1
    Chanukah started on a Friday in 2000 hebcal.com/converter/?hd=25&hm=Kislev&hy=5761&h2g=1 – Double AA Dec 19 '16 at 21:15
  • The rarest Keviah is Thursday-355 – Double AA Dec 19 '16 at 21:18
  • 1
    My father once wrote a program for exactly this, and published a table in the Danish Jewish community's newsletter, Jødisk Orientering. Wonder if I can dig up the code... – Adám Dec 19 '16 at 21:36

I'm not aware of any online resources for what you are seeking, but I happen to have created a helpful calendar in Excel, and have made the first 6000 years available as a Google Sheet here.

For your purposes, you could use a COUNTIF formula on column I for the period you are interested in, which will return the number of years of that type in the given period.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .