Books

Ninjutsu Book References

Below is a curated list of important Ninjutsu-related literature and reference books.

The original historical documents of the Bujinkan schools are not stored in a museum — they are preserved by Hatsumi Sōke himself. Most of this historical material has already been published by Hatsumi Sensei in his English-language books, so those titles are not included here. The list below contains only books published in Japanese.

• Old Documents (This is known documents you can find in museums)
• General Books (This is published books of interest)

Historical Background

According to the Nihon Shoki, the first recorded ninja-like act took place during Emperor Jinmu’s eastern expedition (667–661 BCE), when Michiomi no Mikoto used Chōka Tōgo (a form of deception) to defeat thieves. Another tradition credits En no Gyoja Ozunu (born around 634 CE) as the founder of both Kōga-ryū and Iga-ryū ninjutsu, linking its origins to his Shugendō practices. Some theories suggest he studied the Shichisho or Tonkōjutsu, but the truth remains a mystery.

Because literacy was extremely rare in historical Japan, ninjutsu practitioners relied almost entirely on memory — a skill that seems almost impossible in today’s short-attention-span world. Without written records, they memorized techniques thoroughly and passed them down orally from master to student. It was only during the peaceful Edo period, when wars finally ceased, that many practitioners gained the time to learn reading and writing, allowing them to begin documenting their inherited knowledge.

Ninjutsu’s secretive tradition meant that masters carefully observed and tested their children or chosen students for the potential to uphold the art. If no worthy successor was found, they would often destroy their documents to prevent the knowledge from falling into the hands of malicious individuals. In addition, countless records were lost through natural and human-made disasters — earthquakes, fires, negligence, and the devastating firebombings of World War II.

As a result, only a fraction of the original ninjutsu knowledge has survived to the present day.

Old Documents

Below is a list of the surviving historical documents and reference books related to ninjutsu.

1. 万川集海 Ban Sen Shūkai
   All Rivers Gather Sea
   In Enpō 4 (1676), Fujibayashi Yasutake of Iga detailed the secret transmissions and autumn tools of forty-nine schools of Iga-ryū Ninjutsu. Adding the military essentials secret record, it becomes twenty-two volumes. The structure consists of:
   ① the origin and development of Ninjutsu,
   ② the spiritual code of ninjas,
   ③ methodology,
   ④ positive ninja and negative ninja,
   ⑤ Ninjutsu and astronomy/weather,
   ⑥ Ninjutsu tools (ninja tools, climbing tools, water tools, opening tools, fire tools). It is considered the most important among ancient Ninjutsu transmissions. Besides the Cabinet Library copy, the Ōhara copy, Fujita copy, Ōzawa copy, Takimoto copy, Sawamura copy, Okimori copy are known.
2. 正忍記 Shōnin Ki
   True Ninja Record
   In Enpō 9 (1681), the military scholar Natori Sanjūrō of the Kishū-ke wrote it. Known as one of the three major Ninjutsu transmission books, it is a secret transmission of the Kishū-ke. The Tokyo Ueno Library copy is a beautiful manuscript on torinoko paper. Unlike Man Sen Shūkai, it is not systematic, writing the techniques of Kishū-ryū Ninjutsu as various transmissions and explaining the mindset for their application.
3. 忍秘伝 Nin Hiden
   Ninja Secret Transmission
   Hattori Hanzō Masanari wrote it in Eiroku 3 (1560). As a transmission book of Iga and Kōga schools, it is a fundamental document alongside Man Sen Shūkai and Shōnin Ki. Regarding the establishment year, there is a theory that it was not Eiroku 3 but written in the Tokugawa period, in the later years of Hanzō.
4. 差出帖 Sashidashi Chō
   Submission Ledger
   Genbun 3 (1534). A record of residents of Kōga.
5. 忍術秘書応義伝之巻 Ninjutsu Hisho Ōgi Den no Maki
   Ninja Secret Book Righteous Secret Transmission Volume
   A scroll transmitted in the house of Yorimiya Shihō no Suke, one of twenty-one of the Kōga Gojūsanka and one of the nine Kitayama families. Written in Tenshō 13 (1585), copied by Takenaka Hanbei in Tenshō 14 (1586), and further cleanly copied in Tenpō 12 (1841) by Morishige, a descendant of the Yorimiya family, for preservation.
6. 伊賀者火術秘善 Igamono Kajutsu Hizen
   Iga Ninja Fire Technique Secret Excellence
   Kan’ei 1 (1624). A transmission book of Iga fire techniques.
7. 筑前筑後肥前肥後探索書 Chikuzen Chikugo Hizen Higo Tansaku Sho
   Chikuzen Chikugo Hizen Higo Exploration Document
   Around Kan’ei 3 (1626). A record mixing measurements and hearsay of the conditions of castles, castle towns, households, and territories in these provinces. A report of the public authority’s secret agents.
8. 讃岐伊予土佐阿波探索書 Sanuki Iyo Tosa Awa Tansaku Sho
   Sanuki Iyo Tosa Awa Exploration Document
   Around Kan’ei 3 (1626). A report of information collected by the public authority’s secret agents in Sanuki and other provinces. It reports, mixing measurements and hearsay, the conditions of castles, castle towns, households, and territories.
9. 忍小鏡之巻（五間忍之害） Nin Shōkyō no Maki (Goken Nin no Gai)
   Ninja Small Mirror Volume (Five Spaces Ninja Harm)
   In Kan’ei 12 (1635), April, a copy made in Kyōhō 11 (1726), December, of a transmission book of Matsumoto Rokueimon and a Ninjutsu book transmitted by Fukuchi Yūsui.
10. 軍記の巻 Gunki no Maki
    Military Record Volume
    In Kan’ei 13 (1636), Ukai Kurōdo Yoritsugu taught Matsuno Gennojō sixty-one illustrated methods of military meteorology observation, a copy of the scroll.
11. 伊賀付差出帖 Iga-tsuki Sashidashi Chō
    Iga Attached Submission Ledger
    In Kan’ei 13 (1636), December, three retainers of the Tsuhama Tōdō clan wrote the names of direct vassals and reported to the feudal lord. Following outside groups, cloak groups, gun groups, and residence guards, fifthly, “Ninja Group” is listed, with twenty names, stipends, and years of service recorded. The stipends are all low, and the rank of positions is junior.
12. 忍法秘巻 Ninpō Hikan
    Ninja Technique Secret Volume
    In Shōhō 6 (1647, May), Inoue Shosaeimon Masayoshi copied the secret transmission of Unshū-den Iga-ryū Ninjutsu for disciples.
13. 忍秘伝 Nin Hiden
    Ninja Secret Transmission
    In Jōō 2 (1653), March, Hattori Mino no Kami Yasukiyo wrote it, transmitted from Hattori Hanzō in Eiroku 3 (1560).
14. 兵法秘要竊盗之巻 Heihō Hiyō Settō no Maki
    Military Strategy Secret Essentials Theft Volume
    In Enpō 3 (1675), Koike Hachirōbei wrote and copied it.
15. 土芥冠讎記 Dokai Kan Shūki
    Earth and Dust Crown Vengeance Record
    Genroku 3–4 (1690–91). A directory and reputation record of daimyo nationwide at the time. It is presumed to have been compiled from secret agents’ reports, describing the personalities and private lives of 243 daimyo.
16. 忍大意 Nin Taii
    Ninja Great Intent
    A record of secret matters of Yoshitsune-ryū secret agents. A transmission book of Miu Jiemon in Kyōhō 9 (1724), August.
17. 忍法書 Ninpō Sho
    Ninja Technique Book
    Kyōhō 13 (1728). Nakatsuji Yoshiemon wrote it. It has strong mystical elements.
18. 忍之極意目録 Nin no Gokui Mokuroku
    Ninja Ultimate Secret Catalog
    In Kyōhō 14 (1729), November, Hiraiwa Zenjirō Nobutaka transmitted it. “Nin no Mokuroku” is a variant of this book.
19. 一子相伝 当流忍大極秘 Isshi Sōden Tōryū Nin Daigokubi
    Single Heir Transmission Our School Ninja Great Secret
    Iga-ryū Ninjutsu transmitted by Ryūno Hankurō Sadakatsu, Akaida Denbei Shigekatsu, and Rikusen Keiji Teru, passed to Kōyase Matayoshi in Kyōhō 16 (1731), November, by Hiraiwa Zenjirō Kurayoshi. A variant is “Tōryū Nin Gokubi Den” (1 volume).
20. 伊賀者由緒 Igamono Yūshō
    Iga Ninja Origin
    Kyōhō 20 (1735). A record of the Iga group residing in Edo.
21. 服部流忍法秘伝 Hattori-ryū Ninpō Hiden
    Hattori School Ninja Technique Secret Transmission
    Written in Hōreki 10 (1760), February, a transmission book of Hattori-ryū Ninjutsu.
22. 伊賀者御由緒之覚書 Igamono Goyūshō no Obegaki
    Iga Ninja Origin Memorandum
    Hōreki 11 (1761), September, a record of the Iga group residing in Edo.
23. 甲陽軍鑑的流 Kōyō Gunkan Teki-ryū
    Kōyō Military Mirror School
    Kansei 1 (1789), perhaps. Ōhara Suma. It has strong mystical elements.
24. 甲賀二十家 Kōga Nijūka
    Kōga Twenty Families
    Kansei 1 (1789). A record of Kōga residents.
25. 福島流忍術之書 Fukushima-ryū Ninjutsu no Sho
    Fukushima School Ninjutsu Book
    A ninjutsu book transmitted by Nojiri Jirōemon Masayoshi, a vassal of Fukushima Masanori, transmitted in Kansei 9 (1797), April, by Terasawa Naozaku and Dōkō Hiroshi, descendants of the ninth Hyōgo no Kami, and treasured by Ishikawa Yamato Genchō Mitsutoku, recopied in Bunka 7 (1810), October.
26. 伊賀者大由緒記 Igamono Daiyūshō Ki
    Iga Ninja Great Origin Record
    Kansei 9 (1797), July, Myōjō Shikinban Iga group leaders Yabe Shōemon, Yukioka Hisaemon, Matsuyama Sōhachirō reported the Iga origin to the shogunate. A copy of the origin record submitted to superior Ōkubo Genban no Kami in Genroku 5 (1692).
27. 甲賀忍之伝未来記 Kōga Nin no Den Miraiki
    Kōga Ninja Transmission Future Record
    Oral teachings of Kimura Okunosuke Yasutake, a Kōga-ryū ninja of the Owari domain, recorded by disciple Chikamatsu Hikonoshin Shigenori, copied in Bunka 2 (1805), August, by Mizuno Tadatoshi, who received it from Owari domain’s Suzuki Sadayoshi.
28. 伊賀問答 忍術賀士誠 Iga Mondō Ninjutsu Gashi Sei
    Iga Question-Answer Ninjutsu Gashi Sei
    A record of Iga-ryū Ninjutsu in question-answer format. Published around Bunka–Bunse (1804–1830). A ninjutsu commentary book in question-answer format.
29. 忍術水鏡 Ninjutsu Suikyō
    Ninja Water Mirror
    A copy of a scroll of ninpō transmitted by Niki Shinjūrō Nagamasa, given to Miroku Seisuke by Takezo Kikuma Nobumasa in the Ansei period (1854–1859).
30. 義経流忍術伝害 Yoshitsune-ryū Ninjutsu Dengai
    Yoshitsune School Ninjutsu Transmission Harm
    Yoshitsune-ryū Ninjutsu, originating from Minamoto no Yoshitsune, practiced in the Fukui domain, where ninjas passed down this ninjutsu book through generations; this book is its catalog. A transmission book of Ihara Ban’emon Yorifumi, the eighth generation from Yoshitsune.
31. 義盛百首歌 Yoshimori Hyakushu Uta
    Yoshimori Hundred Poems
    Ise Jirō Yoshimori taught ninjutsu secrets in one hundred poems. It became the origin of ninja songs later created by ninjas.
32. 伊乱記 Iran Ki
    Iga Disturbance Record
    A record of the affairs of Oda Nobunaga’s attack on Iga in the Tenshō period (Tenshō 5 = 1577). It depicts local lords vying for power after the Kamakura shogunate’s fall, including performing strange techniques like fire techniques and stratagems, and also depicts the daily life of Iga ninjas.
33. 忍術秘伝竊忍目錄 Ninjutsu Hiden Setunin Mokuroku
    Ninja Secret Transmission Stealth Ninja Catalog
    Date and author unknown. A transmission book of Akutagawa-ryū Ninjutsu.
34. 甲陽軍鑑 Kōyō Gunkan
    Kōyō Military Mirror
    Written by Obata Kanbei.
35. 大和志料 Yamato Shiryo
    Yamato Materials
    Unknown. It is said to have descriptions about Momochi Tanba.
36. 三河後風土記 Mikawa Go Fudoki
    Mikawa Later Local Record
    Unknown. It is said to have descriptions about Hattori Hanzō Masanari.
37. 武教全書 Bukyō Zensho
    Complete Book of Military Teachings
    Written by Yamaga Sokō (1622–1685).
38. 武術書 Bujutsu Sho
    Martial Arts Book
    Written by Satō Nobutake (1767–1850).
39. 甲賀組由緒書 Kōga-gumi Yūshō Sho
    Kōga Group Origin Book
    Tenpō 10 (1839), August.
40. 楠流火術 Kusunoki-ryū Kajutsu
    Kusunoki School Fire Technique
    Keiō 2 (1866). Transmission unknown.
41. 伊賀者火術秘書 Igamono Kajutsu Hisho
    Iga Ninja Fire Technique Secret Book
    Kan’ei 1 (1624).
42. 伊賀者火術秘伝書 Igamono Kajutsu Hidensho
    Iga Ninja Fire Technique Secret Transmission Book
    Kanbun 12 (1672).
43. 忍術伝書 Ninjutsu Densho
    Ninja Transmission Book
    An Iga-ryū secret transmission book. Date unknown. Many descriptions of ninja tools. Co-authored by Utsukawa Hansuke, Han’emon, Hanbei.
44. 出抜忍之巻 Denuki Nin no Maki
    Stealth Ninja Volume
    A volume of Kaji-ryū military strategy ninjutsu from the Hattori-ryū of Iga, written by Kaji Tōemigami Kagehide. Date unknown.
45. 軍髄応童記忍之巻 Gunzui Ōdōki Nin no Maki
    Military Essence Response Child Record Ninja Volume
    One volume among eighteen combined volumes. Date unknown. A secret transmission of Natori-ryū, written by Natori Sanjūrō Masazumi.
46. 当流忍衆覚語之抄 Tōryū Ninshū Kakugo no Shō
    Our School Ninja Group Memorandum Teachings
    A transmission book writing the memorandum teachings of Yoshitsune-ryū Ninjutsu.
47. 楠流奪口忍之巻 Kusunoki-ryū Dakukō Nin no Maki
    Kusunoki School Seizure Mouth Ninja Volume
    Extending to thirty-nine articles.
48. 草陰火沸錄 Sōin Kabairoku
    Grass Shadow Fire Boiling Record
    Has strong mystical elements.
49. 伊賀流忍術隠火之巻 Iga-ryū Ninjutsu Inka no Maki
    Iga School Ninjutsu Hidden Fire Volume
    Illustrations of fire tools used by Iga-ryū ninjas.
50. 陵問三略 Ryōmon Sanryaku
    Mound Question Three Strategies
    Has strong mystical elements. A secret transmission book of enemy reconnaissance.
51. 八門遁用之巻 Hachimon Tonyō no Maki
    Eight Gates Stealth Use Volume
    Has strong mystical elements.
52. 神伝忍術秘善 Shinden Ninjutsu Hizen
    Divine Transmission Ninja Secret Excellence
    Has strong mystical elements.
53. 竊盗秘密手鑑 Settō Himitsu Tekan
    Theft Secret Handbook
    A fire technique book.
54. 甲賀古士由緒書 Kōga Koshi Yūshō Sho
    Kōga Old Samurai Origin Book
    A record of Kōga residents. Written by Ukai Katsuyama.
55. 甲賀二十一家先祖書 Kōga Nijūikka Senzo Sho
    Kōga Twenty-One Families Ancestor Book
    A record of Kōga residents.
56. 甲賀郡古士伝 Kōga-gun Koshi Den
    Kōga District Old Samurai Transmission
    A record of Kōga residents.
57. 大吼雀問答 Daikōjaku Mondō
    Great Roaring Sparrow Question-Answer
    Has strong mystical elements.
58. 古事類苑 Koji Rui’en
    Garden of Ancient Matters
    In Meiji 12 (1879), a compilation department was established by the Ministry of Education, and through the hands of the Tokyo Academy and the Imperial Classics Research Institute, it reached the Jingū Office, completed in Taishō 2 (1913). A so-called official encyclopedia, divided into thirty sections such as heaven, seasonal events, earth, Shinto, emperors, official ranks, fiefs, politics, law, currency, weights, diplomacy, military and martial arts, religion, literature, rituals, etc., with general explanations and fundamental historical texts cited for each item. Separate general catalog and index exist. The cited book in this work is the military section’s espionage and stratagem compilation.

Hatsumi Books

1. いま忍者 Ima Ninja
   Now Ninja
   Written by Hatsumi Yoshiaki. Published in Shōwa 56 (1981), January. Chōbunsha. The author is the 34th soke of Togakure-ryū Ninpō.
2. 戦国忍法図鑑 Sengoku Ninpō Zukan 🥷✓
   Sengoku Ninja Technique Illustrated Guide
   Supervised by Higuchi Kiyoyuki, written by Hatsumi Yoshiaki. Published in Shōwa 53 (1978), April. Shin Jinbutsu Ōraisha. The author is the 34th soke of Togakure-ryū Ninpō Happō Hikenjutsu and other eight school headships.
3. 戸隠流忍法体術 Togakure-ryū Ninpō Taijutsu
   Written by Hatsumi Yoshiaki. Published in April 25’th Showa 58 (1983), Tsuchiya Shoten.
4. 君にもなれる忍者 Kimi ni mo Nareru Ninja 🥷✓
   You Too Can Become a Ninja
   Written by Hatsumi Yoshiaki. Published in Shōwa 59 (1984), January. Akebono Shuppan. The author is the 34th soke of Togakure-ryū Ninpō.
5. 半棒術・十手・鉄扇 (武道選書) Hanbōjutsu, Jutte, Tessen (Budō Sensho) 🥷✓
   Written by Hatsumi Yoshiaki. Published in September 10’th Showa 59 (1984), Tsuchiya Shoten.
6. 棒術―写真で覚える (武道選書) Bōjutsu — Shashin de Oboeru (Budō Sensho) 🥷✓
   Written by Hatsumi Yoshiaki. Published in September 20’th Showa 61 (1986), Tsuchiya Shoten.
7. 槍術―写真で覚える (武道選書) Sõjutsu — Shashin de Oboeru (Budō Sensho) 🥷✓
   Written by Hatsumi Yoshiaki. Published in October 20’th Showa 61 (1986), Tsuchiya Shoten.
8. 世界のマーシャルアーツ (武道選書) World Martial Arts In The World 🥷✓
   Written by Hatsumi Yoshiaki. Published in April 10’th Showa 62 (1987), Tsuchiya Shoten.
9. 秘伝 戸隠流忍法 Hiden Togakure-ryū Ninpō 🥷✓
   Secret Transmission Togakure School Ninja Techniques
   Written by Hatsumi Yoshiaki. Published in Heisei 2 (1990), April. Tsuchiya Shoten. The author is the 34th soke of Togakure-ryū Ninpō.

General Books

Below is a list of published books in Japanese from the early 1900’s.

1. 忍術秘録 Ninjutsu Hiroku 🥷✓
   Ninja Secret Record
   Written by Fujita Seiko. Published in Shōwa 11 (1936), August. Chiyoda Shoin. The author is the 14th soke of Kōga-ryū.
2. 法術行り方繪解 Hōjutsu okonai-kata ezetsu 🥷✓
   Illustrated Explanation of the Manner of Performing the Arts of the Law
   Written by Fujita Seiko. Published in Shōwa 3 (1928), October. The author is the 14th soke of Kōga-ryū.
3. 甲賀流忍術 Kōga-ryū Ninjutsu
   Kōga School Ninjutsu
   Written by Fukuyama Matsusui. Published in Shōwa 28 (1953), November. Jinrui Kagaku Kenkyūjo publication. The author is a former local police superintendent.
4. 忍術 Ninjutsu 🥷✓
   Ninjutsu
   Written by Adachi Makiichi. Published in Shōwa 32 (1957), December. Heibonsha.
5. どろんどろん Doron Doron 🥷✓
   Doron Doron
   Written by Fujita Seiko. Published in Shōwa 33 (1958), October. Nihon Shūhōsha.
6. 忍術 その歴史と忍者 Ninjutsu Sono Rekishi to Ninja 🥷✓
   Ninjutsu: Its History and Ninjas
   Written by Okuse Heishichirō. Published in Shōwa 38 (1963), September. Jinbutsu Ōraisha. Revised edition in Heisei 7 (1995). Shin Jinbutsu Ōraisha. The author is a leading ninja researcher residing in Iga, Ueno-shi.
7. 忍者の生活 Ninja no Seikatsu
   The Life of Ninjas
   Written by Yamaguchi Masayuki. Published in Shōwa 38 (1963), February. Yūzankaku Publishing.
8. 忍法 その秘伝と実例 Ninpō Sono Hiden to Jitsurei
   Ninja Techniques: Their Secret Transmissions and Examples
   Written by Okuse Heishichirō. Published in Shōwa 39 (1964), October. Jinbutsu Ōraisha. Revised edition in Heisei 7 (1995). Shin Jinbutsu Ōraisha.
9. あなたも忍者になれる Anata mo Ninja ni Nareru
   You Too Can Become a Ninja
   Written by 名和弓雄 Nawa Yumio. Published in Shōwa 41 (1966), August. Keibunkan.
10. 仙人の研究 Sennin no Kenkyū
    Study of Hermits
    Written by Chigiri Hikari. Published in Shōwa 51 (1976), August. Tairiku Shobō. The author is a member of the theater association.
11. 忍者と盗賊日本史・陰の人物誌 Ninja to Tōzoku Nihonshi, In no Jinbutsushi
    Ninja and Thief Japanese History: Chronicles of Shadow Figures
    Written by Tobe Shinjūrō. Published in Shōwa 53 (1978), October. Nihon Shoseki Kabushiki Kaisha. Paperback edition in Shōwa 61 (1986), Kawade Shobō Shinsha.
12. 戸隠の忍者 Togakure no Ninja
    Togakure Ninjas
    Written by Shimizu Basan. Published in Shōwa 57 (1962), August. Ginga Shobō.
13. 甲賀の歳月 Kōga no Saigetsu
    Kōga’s Years
    Edited by Yuzuki Tōsō. Published in Shōwa 62 (1987), March. Seishūdō. The author manages Seishūdō bookstore and Kōga Ninja Village.
14. 忍者の履歴書 Ninja no Rirekisho
    Ninja’s Resume
    Written by Tobe Shinjūrō. Published in Shōwa 62 (1987), April. Asahi Shinbunsha.
15. 考証忍者物語 Kōshō Ninja Monogatari 🥷✓
    Verified Ninja Stories
    Written by Tamura Eitarō. Published in Shōwa 63 (1988), August. Yūzankaku Publishing. The author is a historian.
16. 歴史グラフィティ 忍者 Rekishi Gurafiti Ninja
    Historical Graffiti Ninja
    Published in Heisei 5 (1993). “Shufu to Seikatsu” Seikatsu Series. Shufu to Seikatsusha.
17. 萬川集海全八巻 Man Sen Shūkai Zen Hachi Kan
    All Rivers Gather Sea Complete Eight Volumes
    Written by 名和弓雄 Nawa Yumio, supervised by Ishida Yoshito. Published in Shōwa 51 (1976). Seishūdō. Modern language translation pocket book.
18. 真説・日本忍者列伝 Shinsetsu Nihon Ninja Retsuden
    True Tales: Japanese Ninja Chronicles
    Written by Koyama Ryūtarō. Published in Shōwa 39 (1964). Arechi Shuppansha.
19. 秘録戦国忍者 Hiroku Sengoku Ninja
    Secret Record Sengoku Ninja
    Written by Miyazaki Atsushi. Published in Shōwa 49 (1974). Tōen Shobō.
20. 異聞忍者列伝 Ibun Ninja Retsuden
    Unusual Tales Ninja Chronicles
    Written by Nomura Toshio. Published in Shōwa 59 (1984). Shunyōdō Bunko.

There is obviously many more books written after the ones listed above provided by Bessatsu Rekishi Dokuhon published in 2001, but I prefer to have older sources than newer sources just repeating older sources. Below is a few books I think should be included.

24. 忍術の研究 Ninjutsu no Kenkyū 🥷✓
    The Study of Ninjutsu
    Written by 名和弓推 Yumio Nawa. Published on November 1, 1972
25. 忍術秘伝 Ninjutsu Hiden 🥷✓
    Ninja Secret Transmission
    Written by 奥瀬 平七郎 Heishichirō Okuse. Published in Showa 34 (1959), by Bonbonsha
26. 忍法・超人の世界 Ninpō Chōjin no Sekai 🥷✓
    Ninja Techniques: The World of Superhumans
    Written by 大平陽介 Ōhira Yōsuke. Published in January, 1975
27. 忍法 Ninpō 🥷✓
    Ninja Way
    Written by 戸部新十郎 Tobe Shinjūrō. Published in August 1978
28. 忍びと忍術 Shinobi to Ninjutsu 🥷✓
    Shinobi (Ninja) and Ninjutsu
    Written by 山口正之 Masayuki Yamaguchi. Published in July 2003
29. 忍者・忍術 Ninja / Ninjutsu 🥷✓
    All Things About Ninja
    Written by 山北篤 Atsushi Yamakita. Published in December 2004
30. 図解隠し武器百科 Zukai Kakushi Buki Hyakka 🥷✓
    Illustrated Encyclopedia of Hidden Weapons
    Written by 名和弓推 Yumio Nawa. Published in May 1977