「かれらは、権力を侮蔑し、その権力に自分の人生と運命を捧げる武士の忠義を軽蔑した。諸国の武士は、伊賀郷土の無節操を卑しんだが、 伊賀の者は、逆に武士たちの精神の浅さをわらう。伊賀郷土にあっては、 おのれの習熟した職能に生きることを、人生とすべての道徳の支軸においていた。おのれの職能にのみ生きることが忠義などとはくらべものにならぬほどいかに凛烈たる気力を要し、いかに清潔な精神を必要とするものであるかを、かれらは知りつくしていた。」

"They despised authority and the loyalty of samurais who gave one's life and destiny to the authority.
Samurais of another provinces looked down on unprincipled Iga, but Iga people derided the shallow mind of samurais.
At Iga, earning their living by only the professional ability was the pivot of their lives and all the morality. They had the thorough knowledge that living by only the professional ability had need of so dignified will-power and so clean mentality."

From "The Castle of the Owl" (Written by Shiba Ryoutarou)

The History of IGA

御斎峠(Otogi Pass)

Iga(伊賀) is near to Kyoto(京都), but it is surrounded by precipitous mountains, Suzuka mountain range(鈴鹿山脈) and Murou mountain range(室生山脈).
Mt Handou(飯道山),Mt Aburahi(油日岳) and Mt Norito(祝詞ヶ岳), many mountain ascetics(修験者, shugen-ja, ) lived in their mountains.
Naturalized people and many nobles who were defeated for the political strife in Kyoto lived there.
The characteristics of Iga people are independence-oriented, anti-Establishment and opportunism.They are cautious with strangers.

In Heian period(平安時代, 9c-12c), the most part of Iga was the shouen (a manor in medieval Japan) of Toudai Temple(東大寺). But Iga people revolted against their rulers and they established the autonomic regime in the14th century.

The republic was called Iga soukoku ikki (伊賀惣国一揆) which hadn't a lord and 12 leading clans had the vote. Iga republic was the merit system, it could become a samurai if an ashigaru(足軽, a common soldier) put up an achievement. But, betrayers were executed and their heads put on public display.

They were skillful at the guerrilla activity, and often participated in the battle as a business soldier in other countries.
1487, the 9th Shogun of the Muromachi shogunate(室町幕府) Ashikaga Yoshihisa(足利義尚) attacked Rokkaku Takayori(六角高頼) personally, Iga and Kouga warriors who were in the employ of Rokkaku repulsed the attack. Since then, Iga-mono(伊賀者Iga-men) and Kouga-mono(甲賀者, Kouga-men) have become synonyms for ninja.

In the16th century, Oda Nobunaga(織田信長), the daimyou (大名, a feudal lord) of Owari(尾張) intended to unify Japan. He exterminated the autonomies of the whole country. Any temples, the merchant city Sakai(堺) and Iga too.
Iga was attacked by Nobunaga in 1579 and 1581. The first attack was repulsed by Iga warriors, but Nobunaga sent 44,000 troops after two years. (The total population of Iga in those days was a little less than 100,000.)

Iga ninjas who survived the massacre were employed by daimyous in the other countries.
On of the jounin(上忍, The mastermind of ninjas families Hattori(服部) clan was taken into Tokugawa Ieyasu's(徳川家康) confidence specially. When Nobunaga was killed by betrayers, Ieyasu had stayed in Sakai together with a few men, he came back to his domain under the escort of Iga and Kouga's warriors.
Subsequently, he became the first Shogun of Edo shogunate(江戸幕府), so Iga-mono and Kouga-mono became the public servants. And Iga was under the control of Toudou Takatora(藤堂高虎)by the order of Ieyasu.
But 1604, Hattori clan was ruined and their genins(下忍, common ninja) were taken away by the government.

伊賀上野城(Iga-Ueno Castle)

(The donjon of Iga-Ueno Castle)
The donjon has been restored 1935.

A rural scene of Iga.
Hattori Clan and Jounin Clans of IGA

(Yahazu-guruma/Notches of arrows and a wheel)
The heraldic emblem of Hattori clan.

In the 12th century, Hattori Ienaga(服部家長) won the tournament of archery in the Imperial presence.
Ienaga was awarded 1,000 eagle's feathered arrows on a handcart by the ex-Emperor Toba(鳥羽) , then he decided his clan's heraldic emblem on "notches of arrows and a wheel".
Since then, many branches of Hattori clan's heraldic emblems are design of arrows.

半蔵門(Hanzou Mon)
This gate is called "Hanzou Mon(Hanzou's Gate)" because Iga mono lived around the west gate of Edo castle.

(Hattori Hanzou Masanari 1542-96)

A common ninja was called "genin (下忍)", and the platoon commander was called "chuunin(中忍)".
Hattori(服部). Momochi(百地) and Fujibayashi(藤林) were the distinguished clans of Iga, they were called jounin(上忍), and held the position of leadership.

They say Hattori clan's ancestors came to Japan from China or Korea in the beginning of the 5th century.
In the Period of North and South Dynasties(1334-1467), Hattori clan expanded their territory by the seizure of many shouens of the north Iga.

Hattori Hanzou Yasunaga(服部半蔵保長, 1513-8?) worked under 12th Shogun of Muromachi shogunate Ashikaga Yoshiharu(足利義晴) at first. But after Yoshiharu passed away, he left Ashikaga family, and served new master Matsudaira Kiyoyasu(松平清康), the lord of Mikawa(三河).

Matsudaira Kiyoyasu's grandson Tokugawa Ieyasu gave Hanzou Masanari(半蔵正成, 1542-96), a son of Hanzou Yasunaga, an important position.
When Iga ninjas were massacred by lord Oda, Momochi and Fujibayashi clans suffered great losses but Hattori clan hardly suffered damage because they have served under lord Tokugawa.
In June 1582, lord Oda was killed at Honnou Temple, Ieyasu came back to his domain under the guard of Hanzou Masanari and many ninjas.
Hanzou Masanari was a great lancer, called "Oni Hanzou(鬼半蔵 Demon Hanzou)".
He distinguished himself on the field of battles.
In 1603, Ieyasu acceded to the shogun of Edo Shogunate, he settled 200 Iga-mono in Yotusuya of Edo. (Because the mansion of Hattori clan was outside the west gate of Edo Castle the gate is called "半蔵門 Hanzoumon/Hanzou's Gate".)

But "Demon" Hanzou Masanari's son Hanzou Masanari(半蔵正就 15??-1615) was not quite the great commander his father had been. In 1606, Iga-mono rebelled against Masanari(the son), this finally brought about his downfall.
Masanari was killed in the battle of Oosaka. And his brother Masashige(正重) incurred the second Shogun Hidetada's(秀忠) displeasure because he was involved in a political scandal.
Finally the main branch of the Hattori clan was ruined, Iga-mono were under the control of Edo shogunate.