Tally Marks

Tally marks, or hash marks, are a unary numeral system. They are a form of numeral used for counting. They allow updating written intermediate results without erasing or discarding anything written down. However, because of the length of large numbers, tallies are not commonly used for static text.

In Europe and North America, tally marks are most commonly written as groups of five lines. The first four lines are vertical, and every fifth line runs diagonally or horizontally across the previous four vertical lines, from the top of the first line, to the bottom of the fourth line (the popular direction may vary from region to region). The resulting mark is known as a five-bar gate, from its similarity to the same. In some variants, the tenth tally is indicated by an X through the previous four rather than just a line, and in still other variants, the diagonal/horizontal slash is used on its own when five or more units are added at once. Two groups of five lines (i.e. ten tally marks) are sometimes circled.

Chinese, Korean, Japanese and Taiwanese tally marks use the five strokes of 正 which is the character meaning "correct", "proper" and "honesty".

Notched sticks, known as tally sticks, also were used for this purpose. The burning of discarded tally sticks resulted in the accidental Burning of Parliament in London in 1834.

Roman numerals and Chinese rod numerals were derived from tally marks, as possibly was the ogham script.

• Tally marks used in most of Europe, Zimbabwe, Australia, New Zealand and North America

• Tally marks used in China, Japan, Korea and Taiwan

• Tally marks used in France, Spain, South America (Argentina, Brazil, Chile, Venezuela and Uruguay, among others) and French-speaking Africa. In Spanish countries, these are most commonly used for registering scores in card games, like Truco

• In the dot and line (or dot-dash) tally, dots represent counts from 1 to 4, lines 5 to 8, and diagonal lines 9 and 10. This method is commonly used in forestry and related fields.