Yes
Amazon.com
And Jesse Enkamp has also spoken of this.
You previously mentioned that ninjas basically stopped being a thing after the Meiji Restoration. Think about the possible reasons for this. During Sengoku, if a ninja assassinated someone from an enemy province, think about what the consequences were for the entity that sent the ninja. Then, think about what the consequences would be if they were sent to China for that purpose. Consequences are much bigger, correct?
Now, imagine what they would be after the Meiji Restoration where Japan was now acting on an international scale. Let's say they send one to Europe to assassinate a high ranking noblemen. What would be the consquences for Japan for doing this? Let's say today: Japan sends one to North Korea to take out Kim Jong-un. Is Japan ready for full-scale war with not only North Korea, but also two other nuclear armed countries (Russia and China) that would undoubtedly rain down the wrath of god upon them? They have no use today.
Putting a link to a site where we have to buy the book to read it is a poor citation to a source. I'm not paying £12 to read it.