How to Get a Good Grade in Ninja School

If you’re a college student, you’ve probably taken a class where only a few data points — an essay or two, maybe a midterm or a final exam — comprise your final grade. As a result, everything you turn in has to be taken seriously; you can’t afford to mess up because there isn’t an opportunity to rebound later. When it comes to essay writing in particular, you’ll want to take the time and care to edit and revise your work, possibly more than a few times, to ensure you get as high a grade as possible.

Or you could spend your time making your own ink. That’s what history student Eimi Haga did — and it turned out to be such a brilliant idea, that the professor didn’t even bother reading her whole essay.

In 2017, Mie University in Tsu, Japan (here’s a map) opened a new department — the International Ninja Research Center, a program dedicated to the history and culture of all things ninja. In the fall of 2019, Haga, then a first-year student at the university, enrolled in a ninja history class. As part of her studies, she visited the Ninja Museum of Igaryu, a popular tourist destination which, as the name suggests, is all about ninja history. Her professor, Yamada Yuji (who serves as Vice President of the Ninja Research Center), asked the class to write an essay about the museum visit. And, as Haga told the BBC, Yuji told the students that “he would give a high mark for creativity.”

Haga took that promise to heart, and instead of spending her time crafting the perfect essay, she bought a bunch of soybeans. Per the BBC, she “soaked soybeans overnight, then crushed them before squeezing them in a cloth. She then mixed the soybean extract with water – spending two hours to get the concentration right – before writing her essay with a fine brush on “washi” (thin Japanese paper).” The reason? When the soybean-based ink dried, the writing all but vanished from the paper. And this was her intent. Haga was putting into practice the ninja art of “aburidashi,” a method of sending secret messages. When the paper is put near a heat source, the writing reappears, almost like magic. It’s not something used today — we have more high-tech ways of sharing our secrets — but it was state-of-the-art for the time. And it was a very cool idea for a student essay in 2019.

As the Guardian reported, she “submitted an essay about the assassins with a message attached instructing the professor to heat it before reading.” And that was enough to impress Professor Yamada. He told the Guardian that “reports filed as scrolls or folded into throwing stars were the most creative he had seen from students until now. ‘We discussed the use of invisible ink but I was amazed that someone actually used it,’ he said.” And he gave Haga an A grade, even though he didn’t read the entire paper. As he told the BBC, “I thought I should leave some part of the paper unheated, in case the media would somehow find this and take a picture.” And they did — you can see Haga’s essay (well, part of it, at least!) at the top of this story.

Bonus fact: In 2018, a professor named Jeffrey Scott Davis gave his students an assignment: “Pick a Marvel character to embody within a resume and cover letter.” One of his students turned in a cover letter with three words, over and over again, and a resume that took a similar approach. Despite the apparent lack of effort, Dr. Davis gave the student an A — because the student followed the directions perfectly. The three words the student used? As seen in this tweet by Davis: “I am Groot.”

From the Archives: The Unforgiving Tyranny of the Red Pen: When teachers grade papers with red pens, they tend to find more errors.