The length of the Ancient Minoan foot and the Ancient Japanese Shaku are nearly identical
This post is in response to questions posed on http://kanashi.net/2011/12/25/the-minoan-seki/
The similarity between the Minoan foot and the the Japanese shaku
These Ancient standards of measurement are, in all probability closely related. At first glance the standards seem to differ by 0.6 mm out of 303 but on further examination they are much closer and in fact could be considered identical.
The Ancient Sumerians in the third millennia BC created a system of measurements which was based on a one second pendulum which was almost one meter long. Distance was measured in multiples of this standard. One of these was a little longer than 1/6 of a nautical mile while the next was about 5 nautical miles. The accuracy of these standards was improved throughout the following centuries
The Minoan foot was derived precisely from the length of a pendulum which swings 366 times in the period the earth rotates 1/366 of its circumference measured on a line of sight to Venus in opposition. The length of this pendulum is doubled then multiplied by 366 to produce a length which is approximately 1/6 arc minute in latitude. The Minoan foot is 1/1000 this distance.
In a similar manner, using the same formula and taking into account the difference in gravity at the two locations as well as allowing for the properties of a real pendulum, the error is well within the measuring ability of these ancient civilizations.
There can be no question that both of these standards are part of the same attempt to replicate a length equal to 1/6 of today’s nautical mile. A standard for accuracy which was only surpassed by the Greeks foot and Stadia.
Today, the arc second and the arc minute (nautical mile) are shown on every chart used today for navigation on both the sea and in the air. Maybe its not so surprising that sea faring nations half a world apart used the same navigational standards so long ago.