North Korea News Podcast by NK News - Stephen Mercado: How Japan crafted secret weapons to counter North Korea

Episode Date: September 18, 2025

This week, Stephen Mercado returns to the NK News Podcast to discuss his new book, “Japanese Spy Gear and Special Weapons,” and how Japan’s secretive Noborito Research Institute supported covert operations targeting the DPRK during the Korean War.  Mercado is a former CIA analyst and open source officer who worked for most of his career […]

You're listening to an exclusive episode of the NK News podcast, available only to subscribers. You can listen to this and other episodes from your preferred podcast player by accessing the private podcast feed. For more detailed instructions, please see the step-by-step guide on the NKNews website at NKNews.org slash private-feed. Hello, listeners, and welcome to the NK News podcast. I'm your host, Jack O'Sweds, and today we're recording this episode via Stream Yard. It is Monday, the 25th of August, 2025, and we have a return guest, and that's Stephen Mercado, a third. former CIA analyst and open source officer who worked for most of his career in the foreign

broadcast information service, later named the Open Source Center and now the Open Source Enterprise. He retired in 2017 and was first on this podcast on the 10th of January last year, 24, on episode 324, back when we were still numbering episodes. Today we'll talk about his newly published book of history called Japanese spy gear and special weapons about scientists and technicians of the Japanese Army's Noborito Research Institute in the Second World War and the Cold War. Welcome back, Stephen Macado. Well, thank you. Thank you for inviting me. And congratulations on the publication of your book. Well, thank you. Thank you. Is this your first published book? No, this is my second book. The first one was published in 2002,

and that was another Japanese history. It was a history of the Japanese Army's Akano School for Intelligence Officers and Commandos. Oh, right. Well, I haven't read that one, but I had a lot of fun reading this one. So, in a sentence or two, for our listeners at home, why should Korea specialists care about the Imperial Japanese Army's Ninth Army Technical Research Institute? Well, they should care because first the story takes place when Korea was part of the Japanese empire, and some of the story takes place in what is today called Busan. where there was a biological warfare project taking place under Japanese direction.

And then second, after the war, people related, people from the Boreto, we're working with the U.S. government during the Korean War to create counterfeit documents used in special operations. So two points where there's a Korean connection. That's a great summary. So what exactly was Noborito and what were its concerns? constituent sections. And Naborito was a research institute that came out of Japanese efforts to expand their, who developed technology foreign World War I.

And specifically, Nabori To was involved in developing the equipment weapons for special operations. The sections, there were three sections, three important sections, and then the fourth section for testing. Our first section, section one, that one dealt primarily with the who became the death rate project. There's experiments with wave technology. Second section was involved primarily with the development of poisons and pathogens for biological operations. And then third section was running the production of fake banknotes for a project to undermine the Chinese economy through the introduction of fake Chinese banknotes. Okay. Now, in your book, and actually at Norbert, we've bundled together really two things that I wouldn't normally think of at the same time, which is on the one hand, spycraft and on the other hand, special weapons, including biological and chemical warfare, but also balloon bombs and the death rate that you've mentioned. So how did they end up in the same institute?

Well, I think the common point to all of them is that they're unconventional weapons, number one, and they're used in special operations. number two. So for example, for biological warfare, the Japanese army was conducting field tests throughout Asia from Manchuria down into Southeast Asia. And for the most part, those were tests for deploying biological weapons, say on the battlefield. Whereas the Boreto was also involved in biological weapons, but poisons. And that was more, I think, for special operations. So, for example, targeted assassinations, the use of poisons and targeted assassinations. It's not an absolute, it's not an absolute division, but I would say that that would characterize Napurito. So special operations, while there were, in the Japanese

army, there were these technical research institutes. There were 10 total. And for the most part, they were developing weapons for the conventional battlefield of developing tanks, rifles, that sort of thing. So only in Naborito, which was the 9th Army Technical Research Institute, did you have this organization developing weapons that would be used unconventional operations? So, for example, when soldiers were sent to the southern islands of Japan, the Liu Q chain, which includes Okinawa, they were sent, among other things. they were sent with pens for poisoning the wells of areas where the enemy would be occupying. So those pens would hold a small quantity of some sort of poison, is that right?

That's right. So that's not a typical, that's not typical army gear. No. So that wouldn't have been developed at the first institute or the second institute, but that's the sort of thing that Nagorito did. Ah. Now after the Japanese surrender in August 1945, the Americans occupied Japan and began questioning members of the Noborito Research Institute. Similar to, I guess, what had happened in defeated Nazi Germany, some members of the Norberto Research Institute came to work for the Americans, often for General Douglas MacArthur's chief intelligence officer of, or G2,

major General Charles Willoughby. That's my nutshell summary of how it worked out. Does that sound more or less accurate? I think that's a lot of it. It was a wide-ranging effort on the part of the U.S. government after the war to thoroughly investigate the science and technology that had taken place during the war, both in Germany and Japan. I suppose they probably did it in Italy as well, but I don't know about that. The German case is well known in the United States because among the people who came to work for the United States was Dr. Vernarvon Brown, who had been involved in V2, the V2 project in Germany, and he later worked. for the United States and the Apollo space program.

So in Japan, too, there was a similar effort looking to see everything that the Japanese had done across the board. And in some cases, this involved interviewing people who'd been at Noborito. Now, is it the case that nobody from Noborito ended up appearing before the Tokyo War Crimes Tribunal? Nobody was brought to trial.

There may have been some witnesses. For example, General Iwakuro, who had been instrumental in setting up Noborito and had been involved in things like the counterfeiting program. I know that he was called to testify in the trial of other officers, but as far as I know, nobody from Noborito, you know, at the working level, went on trial for what he did. And was that perhaps part of a kind of a tit-for-tat deal,

that if they were, you know, giving of technology to the Americans, that they wouldn't be prosecuted? I think so. I think that's the case. There's testimony that, for example, in the case of the counterfeiting, that the Americans spoke of give and take so that in return for working with the Americans on things like, say, document forgeries, that they would not prosecute them or turn them over to the Chinese. For example, the Chinese probably would have prosecuted the Japanese who had been involved in the counterfeiting program because that is a very serious crime. counterfeiting and other nation's currency with the intent for destroying the economy. Right. Right. Yeah. And let's start with the counterfeiting effect. So we'll begin with this two-story building inside the newly created U.S. naval base in Yokosuka, which housed an organ

with an very innocent sounding name, the government printing supplies office or GPSO. And you write that the GPSO included rooms for analysis, papermaking, and printing. And you describe how these ex-Nobrito or document forgery specialist worked there at the GPSO alongside American intelligence officers before and during the Korean War. And what specifically were they producing for Korean Peninsula operations? Well, it seems that they were producing a wide variety of products. I think some of them were what they called notebooks for the soldiers. I guess North Korean soldiers would have some sort of notebook that they would carry with them. There would be the identification documents, you know, complete with photograph and you know the usual information you would find on such documents

there were people who are operating during the korean war as in disguise of fishermen or laborers and presumably they would have on them things like ration cards their own identification documents and other things that you would need to produce when challenged by a soldier or policeman asking to see your identification yeah so this is a very important part of of operations when you send agents behind enemy lines, you have to create a convincing cover for them. And so they need the documents to show who they are. This is called agent authentication. So that's what they were doing in your coast because they were working with the Americans to produce the documents needed by people who would be acting as though they were KPA soldiers or dock workers or peasants

or what have you so that they could go behind the lines and survive. Yeah. And your book links the government printing supplies office products to Korean, sorry, the Korea liaison office or KLO, which was General Willoughby's organization of Koreans operating behind enemy lines north of the 30th parallel, as well as to the activities of the U.S. 8th Army and the combined command for reconnaissance activities, Korea, with an interesting name, I don't know whether to pronounce it, C-crack or Crack, and also to Colonel Jack, Canon's Canon agency. I think we talked about him the last time you're on the podcast earlier last year. But basically, what documentary trail ties the GSO output to these specific units?

Well, first, I have to admit that there's no government documents tying this together. That would be very surprising if such documents, if they still exist, wherever we released. So a lot of this comes from people who wrote their memoirs. Basically, their members. Yes, for example, there was a rock Navy officer named Janjong who participated in some of these operations behind enemy lines. He had knowledge of where the documents came from that he and his people were using. Janjong, he'd been in Japan studying when he volunteered as a student to join the Japanese military.

I'm not sure if it's true volunteering, but that's how it's described. He was assigned to the Japanese Quintang army in Manchuria. When the war ended, he made his way back to Seoul and joined the Rock Navy. And then in 1949, a wilded officer of that Navy, he was assigned to Tokyo under General Willoughby's command G2 to the Z, to the Z or the Z unit, which is the unit that Jack Cannon was running. Curious to hear the rest? Become an NK News subscriber today for access to the full episode. Head to NKNews.org slash join for more information.

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