At the dawn of the development of watchmaking, master craftsmen generally had no understanding of how the dial should look. Round – yes, as the Sun, the measure of time, can be observed making a clear circular motion across the sky. The next question was how many units of time should be marked on the dial. This wasn’t clear. Originating from the ancient Sumerians (though it is quite possible it had been invented before them), the custom of dividing the day into 24 hours was taken up by the ancient Babylonians, followed by the Egyptians. The day was thought to consist of 12 ‘day’ hours – from sunrise to sunset – and 12 ‘night’ hours, from sunset to sunrise. Since that moment, the 24-hour day has taken root. From our modern perspective, this counting of the hours wouldn’t have been very convenient in practice, necessitating one set of hours for the day and another for the night. But that is for us, accustomed to the uniform calculation of time counted right down to the billionth of a second by caesium, rubidium and other atomic clocks. Our ancient ancestors had to be content with calculating time using only the course of the celestial bodies – the most accurate clock of the period.
The first mechanical clocks appeared in Europe at the end of the 13th century, and to start with they didn’t have dials, instead simply announcing the time through a chiming bell – based on those same 24 hours. A simple calculation suggests a 24-hour chiming system, with the number of chimes matching the number of the start hour, will require 1 + 2 + 3 + … 22 + 23 + 24 chimes, a total of 300 chimes per day. The mechanism required the inclusion of a 24-step counting wheel. Early mechanical clocks were not energy efficient and complicated mechanics were expensive. Understandably, clockmakers wished to make it easier to manufacture and service their clocks, while their customers wanted to minimise costs. It is also not hard to imagine that for citizens it wasn’t easy to work out the current hour, especially when it was announced with two dozen chimes. It isn’t known what led to the situation changing, but the result certainly is – from about the 15th century Italian clockmakers mostly switched to the so-called Roman method of counting the time (the sistema orario alla romana or sistema orario a 6 ore), with 24-hour days traditionally starting around half an hour after sunset (or, to be more precise, after the evening rendition of the “Ave Maria” prayer in churches), and these days were divided into four 6-hour periods. From a mechanical point of view, switching from 24-hour devices to 6-hour devices meant for a simpler design requiring less energy – a 6-hour cycle reduced the number of chimes to 84 per day, giving significant savings both in terms of mechanics and in the power needed. Incidentally, a 12-hour chiming clock gives a total of 156 chimes per day. The citizens had one remaining problem – they had to work out what time of day it was outside, whether night, morning, day or evening. But even an infant could count the six chimes of such a clock.
On the other side of the Alps an alternative system spread, based on two 12-hour periods. This division of the methods of calculating the time existed until the end of the 18th century, namely until French revolutionary troops conquered Italy. These events are known as Napoleon’s Italian campaign (1796–1797). A few years earlier revolutionary France gad introduced a decimal time system and revolutionary calendar, but on 7th April, 1795, shortly before invading Italy, France stopped the obligatory use of this system. So, Napoleon, on behalf of revolutionary France, introduced in Italy not revolutionary, but pan-European duodecimal time system. The 6-hour Roman system was just as easily abolished upon the occupation of Italy. After the fall of Napoleon, the papal throne attempted to restore the good old order, but to no avail.
A number of Italian municipal clocks with 6-hour dials still survive to this day, in one form or another. Around 250 of these clocks are known to exist, at least according to information carefully collected on the Wikipedia page dedicated to this type of clock. Alas, in a number of cases only the dials survive, apparently only thanks to the unbreakable love that Italians have for ancient artefacts and architecture. (I will note in brackets that it is especially amusing to see attempts to recreate the functionality of the dial, carried out by overly caring keepers, who replaced the lost hands with the gnomon from a sundial. Obviously, the 6-hour dial is not suitable for this role.)
Modern watchmakers and brands, including those from Italy, in general don’t recall that history. Konstantin Chaykin is the exception, linking this story with the Russian custom of dividing the day into four 6-hour periods – night, morning, day and evening. Therefore, he considers his 2012 reinvention of the 6-hour system not to be Roman, but Russian – the system of “Russian hour”. Unlike the old Italian masters, this Russian master did not aim to simplify the mechanics. On the contrary, the movement of his watch is rather complicated, making it comparable with a classic of complex watchmaking – that of the perpetual calendar. How did it happen? The reason comes from Chaykin’s desire to perfect the functionality of the watch.
When starting the development of the movement, he first of all plugged the gap left by the old Italian craftsmen by equipping the watch with a period of day indicator. At the same time, he was able to tie the 6-hour dial with the universally-accepted 12-hour system of calculating the time, having made the scale for the hour indicators in the form of small apertures. When the period of day changes, the numbers ‘6, 7, 8, 9, 10, 11’ are switched to ’12, 1, 2, 3, 4, 5’, and vice versa. In order for the watch to be truly comfortable for the wearer, he opted to make the switching of both the hour and period of day markers an instantaneous process. This, together with the one-directional switching of the period of day marker and bi-directional switching of the hour markers, made the mechanics incredibly complicated. Konstantin admits: “If the indexes on the display did not switch instantly, the watch would certainly cost less. But they implement the instant switching of the indexes and markers of the periods of the day – this requires much more effort. And unlike a watch with a jumping hour indicator, the disk with the hour markers of the Quartime watch does not rotate in one direction, but moves back and forth every six hours – this is much more difficult to implement.”