What is "II III IV V VI VII VIII IX X" on some pocket watches?

"II III IV V VII VIII IX X" on the pocket watch is the Roman numeral of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. A scale indicating time and hour.

The most common Roman numerals are the dial symbols of clocks and watches: I, II, III, IV, V, VI, VII, VIII, VII, IX, IX and VIII.

Roman numerals were used in Europe before the introduction of Arabic numerals (actually Indian numerals), but they are rarely used now. It came into being later than the numbers in China and Oracle Bone Inscriptions, and even later than the Egyptian decimal numbers. However, its appearance marks the progress of an ancient civilization. It's just that there is no size 0.

Roman numerals were used before Arabic numerals appeared. Roman numerals use seven Roman letters as numerals, namely I( 1), X( 10), C( 100), M( 1000), V(5), L(50) and D(500).

The method of counting is. When the same numbers are written together, the number represented is equal to the number obtained by adding these numbers, such as ⅲ = 3; The small number is to the right of the big number, indicating that the number is equal to the number obtained by adding these numbers, such as ⅷ = 8, =12; Small numbers (limited to I, X and C) are to the left of large numbers, which means that the number is equal to the number obtained by reducing the number of large numbers, such as Ⅳ = 4 and Ⅶ = 9.

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Why do Roman numerals on watches use IIII instead of IV?

Roman mythology can explain why IIII was used at that time. At that time, the highest god in Rome was Jupiter. In Latin, Jupiter is spelled IVPPITER. The Romans might hesitate to engrave the name of their supreme god on a sundial or print it on a book. They thought it was disrespectful.

This is why it is still used even if it is inconvenient to write IIII. Although the appearance and maturity of sundial and watchmaking industry are out of date, craftsmen still adopt it because IIII was used more in the early days.

For ordinary citizens who have no education, IIII is easier to understand, although the written Roman numeral (IV) is widely used as a count.

But for some watchmakers, whether to use IIII or IV is still a question that should be hesitated. After all, before the popularity of watches, the most primitive clock was installed at the top of the church as a unique position to display the city time, and there was no room for carelessness.

Using IIII to make watches has a simpler process. For watchmakers, if the addition rule is used, there will be much less molds to be made when making watches. Using IIII is simpler in technology (i, II, III, IIII, v, VI, VII, VIII, VIIII, x, XI, XII), while using IV to make clocks requires 17 "i", 5 "v" and 4 "x". Using IIII means that you need 20 "I", 4 "V" and 4 "X".

If IIII is used, craftsmen only need to make 1 group "VIIIIIX" and then make 3 copies. The first group is divided into five-one-three-ten groups, the second group is divided into six-three-nine groups, the third group is divided into seven-two -XI groups, and the fourth group is divided into eight -IIX groups. Considering the cost, the watchmaker only needs four modules of VIIIIIX to divide the required 12 characters, while the more classic IV dial will need additional molds.

Baidu encyclopedia-Roman numerals