# Coin System from the Talmud -- the Selah, Darkon and Dinar

in Rambam Hilchos Shekalim Perek 1 Halachos 2-4, the basic coinage system is like this:

• 1 Isar = 8 Perutahs. = 4 barley kernels
• 1 Pundyon = 2 Isarin.
• 1 Me'ah/Gayrah = 2 Pundyonin. = 16 barley kernels
• 1 Dinar = 6 Me'ain.
• [Shekel in times of Moshe = 320 barley kernels in weight, not sure what it corresponds to here]
• 1 Sela = 1 Shekel in 2nd Temple Times = 4 Dinarin = 384 barley kernels (weight).
• 1 Darkon = 1 Shekel at a certain time = 2 Selain.

and from this chart on dafyomi.co.il, I get these added to the others (so far no problem):

• 1 Dinar Zahav = 25 dinarim
• 1 Maneh = 4 Dinar Zahavim
• 1 Maneh Shel Kodesh = 2 Manehim
• 1 Kikar = 60 Maneh Shel Kodesh
• 1 Kikar shel Kodesh = 2 Kikarin

The problem:
First, on the chart, although the 25 dinarim are correct for 1 dinar zahav, but it also says that 3 + 1/8 selas are 1 dinar zahav, but according to Rambam that would actually be 3 + 1/8 Darkonos! (Because 1 Darkon according to Rambam is 8 Dinarin and 25 Dinarin are in a Dinar Zahav so that means 25/8 Darkonos are in a Dinar Zahav, which is the same as 3 + 1/8 (which it says on the chart for the number of selaim!)), and that would mean that since 1 Darkon is 2 Selaim, so that means that 3 + 1/8 Darkonos = 2 * (3 + 1/8) Selaim = 6 + 1/4 Selaim, so according to the Rambam 6 + 1/4 Selaim = 1 dinar zahav, while according to this chart 3 + 1/8 selaim = dinar zahav (and the chart doesn't even mention darkonos, not sure if it's relevant though)