北条忍者 Hōjō Ninja (Page 116-117) from the book Bessho Rekishi Dokuhon Vol. 72 – Shinobi no Mono 132-nin Data File. Written by 清水昇 Shimizu Noboru (Writer).
▽ Hōjō Ninja – 北条早雲 Hōjō Sōun and 風魔一党 Fūma Ichitō

Since invading 伊豆 Izu in Meiō 2 (1493 CE), with strategy and bravery as banners, rising rapidly to a leading 戦国大名 Sengoku Daimyō (1467–1603 CE), the first of the Later 北条 Hōjō clan, 北条早雲 Hōjō Sōun.
After the 応仁の乱 Ōnin no Ran (1467–1477 CE), in an era of local uprisings, not only 早雲 Sōun but warlords of every province dispatched spies, so-called ninjas, to various provinces, grasped information, devised strategies, advanced armies, carved out territories, and expanded influence. For warlords of the chaotic era, using strategies and stratagems to conquer was not 卑劣 Hiretsu (base) but rather a standard strategy.
Ninja information held the key to victory or defeat. 早雲 Sōun also dispatched excellent ninjas to battles, and through five generations—氏綱 Ujitsuna, 氏康 Ujikuni, 氏政 Ujimasa, 氏直 Ujinao—over about one hundred years (1493–1590 CE), built the 北条 Hōjō kingdom centered in 小田原 Odawara, dominating Kanto.

As for those ninjas, while ninja groups from 甲賀 Kōga or 伊賀 Iga were called shinobi or ninjas, in other provinces they were called 乱波 Rappa, 透波 Suppā (素波 Soba), 突波 Toppa, and those lurking in grass for reconnaissance were called 草 Kusa. According to the “武家名目抄 Buke Meimoku Shō,” in Kanto they were called Rappa, and west of 甲斐 Kai they were called Suppā. Regarding the background and activities of Rappa, Soba, 三浦茂正 Miura Shigesama, who served 北条氏政 Hōjō Ujimasa and wrote “北条五代記 Hōjō Godai Ki,” states:
“Formerly, the Kanto provinces were in chaos, ceaselessly taking up bows and arrows. 其比らっぱ Sonokoro Rappa and many villains existed. 是ら Korera’s people were thieves, yet not thieves. They were clever-hearted, valiant, and perverse people.”

In other words, they plundered as thieves but judged situations accurately, recorded as fearless people overflowing with loyalty.
It continues further:

“However, the country’s daimyo supported 此者 Konomono. What is the reason for this? These Rappa skillfully 穿鑿 Sensaku and sought out thieves in our country, cut off their heads, infiltrated other provinces themselves, excelled at plundering as 山賊 Sanzoku (mountain bandits), 海賊 Kaizoku (pirates), night attacks, and robbery. With intelligence, their strategizing and maneuvering surpassed ordinary thought.”
This is none other than the Hōjō ninjas who, blending into the darkness, conducted espionage and surprise attacks, leading the five Hōjō generations to victory, and if named as a school, used 北条流 Hōjō-ryū and were called Rappa, the true identity of the shinobi. And this Hōjō ninja group was none other than the 相州乱波 Sōshū Rappa, led by 風魔小太郎 Fūma Kotarō, exceeding two hundred people of the 風魔一党 Fūma Ichitō.

Fukyo depicted in the illustrations of the Manji edition of “The Chronicles of the Five Generations of the Hojo”
風魔 Fūma is said to have taken the name from living in 風間谷 Kazama-dani of 足柄下郡 Ashigara-shimo-gun, 相模国 Sagami-koku (Kanagawa Prefecture), but their origin is completely unknown. One theory says they were a cavalry group that migrated from the continent. Nevertheless, Hōjō Sōun valued the bold and fearless ninja skills of the thieving 粉い Maga clan in 風間谷 Kazama-dani, using them as spies. This is considered the start of 相州忍者 Sōshū Ninja, Rappa, and the heads of 風魔一党 Fūma Ichitō were called 小太郎 Kotarō through generations.
[Picture: 風魔小太郎 Fūma Kotarō held sway with a stronghold in 足柄山 Ashigara-yama (present 金時 Kinji) (Photo / 南足柄市 Minamiashigara-shi)]
北条忍者 Hōjō Ninja (Page 116-117) from the book Bessho Rekishi Dokuhon Vol. 72 – Shinobi no Mono 132-nin Data File. Written by 清水昇 Shimizu Noboru (Writer).
I could not find much information about this book, who wrote it or the publisher. It looks like it was published as a history book/magazine published monthly.
Being the 72’nd book I guess it has been around for many years, the web site jinbutsu.co.jp is dead so I don’t know much about the publisher.

Published May 2001
228 pages
ISBN-10 : 4404027729
ISBN-13 : 978-4404027726