1. A Red Correction on an Ancient Egyptian Board in the Metropolitan Museum
In the collection of the Metropolitan Museum of Art, there is a wooden board from the Middle Kingdom period (around 1981–1802 BCE). The board measures about 43 x 19 cm [2]. On the board, a trainee scribe wrote out a model letter. However, there were many writing errors. According to explanations by Egyptologists, the person who corrected these errors with red ink is believed to be the teacher in charge of the class [1]. The phrase "believed to be" is used because the name of the person who made the corrections is not written on the board. This looks like the origin of red-circle grading, but first, we wonder: why was red chosen?
2. Why Ancient Egyptians May Have Used Red Ink to Signal "Look Here"
In ancient Egypt, it is said that the main text was written in black ink, while red ink was often used for headings, instructions, or words that needed to stand out [3]. Among lines of black text, red text can be distinguished at a glance. It is thought that the teacher used red for corrections so that the corrected spots would catch the eye and leave an impression. However, this is a guess. There are no records from that time explaining why red was chosen [3]. There is another interesting point about this board. The surface was coated with plaster, which allowed old writing to be painted over in white to create a "blank state," so it could be used for practice many times [2]. The cycle was: write, get corrected in red, whiten it out, and write again. Red corrections existed within this repetition. So, how has the habit of adding red to writing been called in Japan?
3. Japanese Words for Corrections, Such as "Adding Vermilion"
In Japanese, there are words like "shu-wo-ireru" (add vermilion), "shu-hitsu" (vermilion brush), and "shu-boku" (vermilion ink). Because corrections were made with vermilion, these terms refer to editing poems, calligraphy, or texts, and the vermilion added for corrections is also called "shu" [4]. In Japanese dictionaries, the red used for editing is the origin of these words. Vermilion is a yellowish-red pigment made from cinnabar (a mineral mainly composed of mercury sulfide). It is used in ink pads and lacquer, but it is considered a toxic inorganic pigment that is weak to sunlight and heat [4]. It is important to note that vermilion is a different color name from the red in today’s red pencils. Vermilion is yellowish-red, while the red in modern pencils is a different color name. So, how is the red pencil used in schools today different from vermilion?
4. How the Red in Red-Blue Pencils Changed from Vermilion
Mitsubishi Pencil Company released the "uni Study/Grading Red-Blue 7:3 Pencil" on April 20, 2022. The company explains that while traditional red-blue pencils used vermilion and indigo-based colors, the new product adopts Red [5]. According to the company, this red is darker than the previous vermilion-based colors, making text in notebooks easier to see. This makes it suitable for grading and color-coding important parts. The 7:3 ratio refers to the core of red and blue. The company states that in learning, many people do the first grading in red and the second check after re-solving in blue. Since red is used more often, they made the red core 7 parts [5]. Red-blue pencils for elementary school students are also introduced as being used for grading, re-checking, and color-coding, with red being used frequently [6]. This is the manufacturer's explanation and one example, not a rule for all schools nationwide. Some people feel the red core breaks easily. This is because colored pencil cores are made by mixing pigments for color with wax and glue, then drying them. They are softer than black pencil cores, which are fired at high temperatures [7]. This is a general explanation for colored pencil cores, and differences exist by manufacturer and product. Red seems to have been chosen because it is easy to see. But does red have power beyond visibility?
5. Do Red Pens Help People Find More Errors?
A 2010 paper by Rutchick, Slepian, Ferris, and others in the *European Journal of Social Psychology* explains that because red pens are associated with errors and poor performance, grading with a red pen may trigger this association [9]. According to reports, participants who held a red pen had a rate of filling in blanks with words related to errors or poor performance that was nearly 30% higher than those with black pens. In a task to find errors in essays, participants with red pens found nearly 30% more grammar and spelling errors than those with blue pens [8]. These figures are from the reports, so it is best to remember them as "about 30% higher." This was an experiment with people who grade work; it does not show that people corrected in red are hurt. Researcher Rutchick reportedly said, "Red pens are not bad, they are just effective." He also said, "If you use purple for 15 years, you could get the same effect" [8]. The view is that the effect comes from the association formed by the long habit of using red as the "color for fixing mistakes," rather than the power of red itself. So, red is good for grading because of both its visibility and the habit of "red is for fixing." Can this habit be used for praise?
6. Why Benesse's "Red Pen Teachers" Value Praise in Corrections
Benesse's correspondence education program, "Shinken Zemi," started for high school students in 1969. According to the company, "Red Pen Teachers" have interacted with a cumulative total of 92 million members [10]. Note that 1969 is the start date of Shinken Zemi, not specifically of the Red Pen Teacher role. The philosophy of Red Pen Teachers is not just praising because work is done. It is based on the idea that if a child first likes themselves, they will also like studying [10]. This is the company's explanation. From red for correcting to red for praising. If you change how it is used, the feeling conveyed by the same red might change. If the association with red is a habit, perhaps habits can be changed little by little.
7. Try It Yourself: Compare Red and Blue Pencils to Decide How to Use Red
If you have a red-blue pencil, try comparing them at the edge of your notebook. On the same paper, write the same characters in red and blue with similar size and pressure. See which one catches your eye more and if thin lines are readable. This is a way to verify the manufacturer's explanation that "red stands out" with your own eyes [5]. Another idea is to add a short comment to the parts you did well, alongside correcting mistakes. If the association that "red is for fixing mistakes" is due to habit [8], you can try changing how you use it to see how your feelings change. The common uses for red pencils seem to be grading, re-checking, and color-coding. Praising is another way to try using it. In which situations do you and your teachers choose red? Pencil tips are sharp, so be careful of injuries when using them.