If you are expecting Korean Ninja, sorry not.
This is rather a proof of there was no Ninja in Korea.
Annals of Joseon Dynasty
Jungjong annals 15
Jungjong 7th May 5th (1512 May)
This record was written 2 years after Sanbo-No-Ran (Riot by Japanese settlers in Korea)
The Japanese prisoner Yoshira (要時羅) testified to the interpreter
"I tell you everything I know because I'm gonna have to be Korean rest of my life.
The Japanese whose family members were killed during the riot asked the lord of Tsushima (So clan) to send troops.
The lord said if they don't make peace, he would plan to send troops to Koje(巨濟).
It is obvious they will come within this year.
It is only 48soku from Tsushima to here, Koreans won't be able to defend if they land during dawn.
And what is more, there are Shinomi(時老未) in Hakata（花加大）.
They are good at disguise. They can sneak into enemy camp like mouse, escape like bird.
No guard can notice.
Tsushima recruited them to set fire on camps.
I heard people from Tsushima talking about it."
The testimony was reported to King and King told to The Military Affairs.
The Military Affairs told to King "What Yoshira said about Tsushima brings people good at disguise from Hakata is ridiculous, it's obvious the story is for scaring us.
But asking Tsushima to take revenge seems to be true. It is better to order to secure defence."
According to Professor Shosuke Murai (Tokyo University), Yoshira is Yoshiro(与四郎) , Shinomi is Shinobi. This testimony proves there were Shinobi in Hakata area in those days. (Of course Hakata is Kyushu Japan) And that means Sengoku war lords were hiring Shinobi.
The Watanabe Documents(150 pages) was discovered in 2000. Koka city has researched the documents since last year and they released some info.
According to Sankei's report, the documents contain exprosive's recipe, instructions for Musket and horseback riding, and some occult arts.
During Edo period, they were hired as "Oshinobi-yaku" by Owari Tokugawa clan.
"Oshinobi-yaku" was like part time job, they were called only needed.
Otherwise, they were living as common farmer.
Nikkei's report says, Oshinobi-yaku was secret contract.
They found 10 written pledges of keeping it secret from family and friends between 1700 ~ 1829.
It seems the Ninjutsu documents were only 17 pages(include the pledges?)
Koka city is going to publish the documents.
Quotes from this book
"This is an old Ninjutsu scroll sold in 8000 Yen. I thought Ninja chain maile was made with iron but this scroll says warp thread is hemp, weft thread is egg plant tree. This is strong enough to block sword and spear. I don't think it blocks spear but probably it prevents sword slashing."
"Ninja scroll usually contains 'no way' technics. For example this says put yam juice around your nose when you are in water then you can breathe. Or write Manji shape on your chest then you won't get drowned."
"Jingu Baseball Stadium (Shibuya) used to be residents for Koka-kumi. There was shooting range."
(Old Guards House)
Working place for (former)Ninja who used to protect the Edo castle.
There are several guard houses(known as checkpoints) from ohtemon to the main edo castle building.
The most strict checkpoint was called “hundred-guards house”.
(Hyakunin means 100 persons.)
At that time, Negoro, Iga, Kōka and Nijugoki were guarding the castle as a last guard house.
If you know some Ninja history, you know Ieyasu hired many Musket Ashigaru from Iga, Koka region when he started new Shogunate government.
They were given Dōshin class which was low rank Samurai.
So they were no longer Ninjas but Tokugawa retainers.
Ref Code C01004864700
Document title 教育用器材特別支給の件 (Educational materials special issue)
昭和１５年１０月１０日(10 Oct 1940)
Page 8 忍術用具(Ninjutsu tools)
To me, this isn't Ninja job.
This kind of job can be done by non-Ninja.
They were spies but not Ninja.
Sneaking into castle is what Ninja job is.