Stay up to date with notifications from The Independent

Notifications can be managed in browser preferences.

Japanese Ninja student gets top marks after writing essay in invisible ink

Ink only becomes visible again when the paper is heated

Stephen Mahon
Thursday 10 October 2019 19:24 BST
Comments
(Shutterstock / beeboys)

Your support helps us to tell the story

From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it's investigating the financials of Elon Musk's pro-Trump PAC or producing our latest documentary, 'The A Word', which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.

At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.

The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.

Your support makes all the difference.

A Japanese student of ninja history impressed her professor by using ancient techniques to submit an essay with invisible ink.

Eimi Haga, 19, followed the traditional method of “aburidashi”, spending hours soaking and crushing soybeans to create the initial substance.

After writing with a fine brush on “washi” (thin Japanese paper), the ink dried and become invisible to the naked eye.

The ink only becomes visible again when the paper is heated. To ensure her professor didn’t put the essay in the bin, she left a note in normal ink advising her tutor to do so.

The professor, Yuji Yamada, told the BBC he awarded full marks for the imaginative effort.

“I had seen such reports written in code, but never seen one done in aburidashi,” he said.

“To tell the truth, I had a little doubt that the words would come out clearly. But when I actually heated the paper over the gas stove in my house, the words appeared very clearly and I thought ‘Well done!’

“I didn’t hesitate to give the report full marks – even though I didn’t read it to the very end because I thought I should leave some part of the paper unheated, in case the media would somehow find this and take a picture.”

The first-year student took a class in ninja history when she enrolled at Mie University in Japan.

“When the professor said in class that he would give a high mark for creativity, I decided that I would make my essay stand out from others,” she said.

“I gave a thought for a while, and hit upon the idea of aburidashi. It is something I learned through a book when I was little.

“I just hoped that no-one would come up with the same idea.”

Join our commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in