Comment Set up a fake comment form as anti-spam measures
It is a so-called negative capture (Negative Captcha), it is an idea to install a form of fake that a bot that enters form input automatically in full automatically, judge it as spam when there is input there, and play it .
If it is not automatic, manual spam has no effect, but if the other person is not Japanese it is possible to trap a further step.
Details are as follows.
Measures against spam and crawlers by honeypot field.
Below is an example of implementing the same in WordPress.
Reduce WordPress Spam By Creating Fake Comment Forms For Spam Bots | OneTipADay.com
Below is a simple example. If you set up a decoy form and hide it as "visibility: hidden" on CSS, it will not be mistaken as humans will not see it when posting.
How We Beat Comment Spam
Furthermore, since most of these comment spams are from foreign suppliers, the following example shows that combining whether or not Japanese can be read will be more effective. It seems to prevent everything unless you can read Japanese. This is a good idea.
Geek's page: Comments from foreign countries Anti-spam measures