Yonagahiko - a god(?) with a human face and a serpentine body - lives on a mountain-side with a small, mysterious boy named Tetsuichi. There is a popular legend about that mountain; a legend which tells the tale of a human who once slew the mountain god and gained possession of his powers...

A scholar with absolutely no desire to study met a mysterious girl called 'Miss Ugly' who had no memories of her past. She was resigned to her fate of being destined to be sacrificed to the Huang Deity, but the scholar was determined to save her.

The story is set in the Edo period of feudal Japan. It revolves around Yamada Asaemon, nicknamed Kubikiri Asa (literally "Neck-chopper Asa", often transliterated as "Decapitator Asaemon"), a ronin who is responsible for testing new swords for the shogun. The character is based on a real-life line of sword-testers who served the Tokugawa Shogunate up to the early 19th century. -- Wikipedia

From Hochuuami:

Prince Ashide decides to agree on a wife, but too bad for him a lone deserter of the country of Ishugal shows up instead to claim the title of Princess.

extra story: Beloved Affair
The older son of feudal lord of Crimson Country, Nagi, loves the surly/arrogant spy, Kari. Kari who always refuses Nagi's courtship happens to know that Nagi loved the lover of his father who had same red eye like Kari. Kari feels anger for Nagi who loves him as substitute...

After the death of the Emperor, the country of Li is plunged into civil war. In order to save his brother's forces from imminent defeat, Xueya, 7th prince of the realm, enters into a marriage with the feisty pirate princess Jin Bi Hui. Will her reinforcements arrive in time to turn the tide? Will this political marriage survive? What would Bi Hui do if she found out Xueya's heart belonged to another?

This manhua based on novel with the same name.

From MangaHelpers:
Suddenly finding himself in the Sengoku era, regular high school student Sagara Yoshiharu is about to be killed in the battlefield. He is saved by none other than the man who later becomes the infamous Toyotomi Hideyoshi but at a cost to his life. With history completely changed because of Yoshiharu’s actions, he tries to make things right again but it seems that history is taking a different course than the one he learned in school. Oda Nobunaga is now a brilliant but young girl named Oda Nobuna. Yoshiharu starts working under her command to bring back history to its correct course and find his way back home to the present world.

The series follows the adventures of Sabu, a young Edo bakufu investigator traveling with the blind master swordsman Ichi. In their travels, they assist the common people in solving mysteries and righting wrongs (usually committed by bandits or corrupt officials). Sabu is engaged to Midori, the daughter of his boss, who works as a police officer for the Tokugawa shogunate.

This series won the 1968 Shogakukan Manga Award.

Set in the Soviet Union, the mysterious girl named Belka and the quiet boy Shchenok help a Socialist Party member to escape from the secret police. Their aim is to infiltrate into a certain mansion that holds what they seek, but the secret police immediately capture the two. Will they be able to find what they seek and endure the torture of the secret police?

One ruler...One schemer...and...One assassin The kingdom of Juushin is suffering at the hands of a cruel emperor. In order to stop his father's rule of tyranny, the crown prince will enlist the aid of a legendary assassin with reasons of her own for wanting the emperor dead.

At the beginning of the Edo period (1603-1868), when people enjoyed a time of peace, Lord Tokugawa Tadanaga decides to hold a fighting tournament. In the past, matches were fought with wooden swords, but this time real swords will be used. The one-armed Fujiki Gennosuke and the blind Irako Seigen will fight each other in this tournament, even though both of them are disciples of Iwamoto Kogan — known as Japan's greatest swordsman. So begins the story of intertwining fates, conflict, and strange destinies.

A reporter discovers an untouched ancient tomb in inland China, which leads to a series of other startling revelations, of the princess of Guangyu, Li Ying, and how she appears in the dreams of Yong Qian, a young teenage girl. Is it possible for modern technology to triumph over an ancient curse?

From Ivyscan:

With her talkative crow Jacky in tow, Daisy Louise goes to London in search of Marie, who has been sold. With the help of Glen, a journalist, will Daisy be able to learn of Marie's whereabouts?

A one shot situated in ancient china, around the Spring and Autumn period. Two childhood friends meet on the battlefield, reminiscing their past before the final battle.

From myobi:

China, early Song Dynasty.

The setting is an era of absolute corruption, when bribery, torture, and threats were the normal way of doing business in the government. Then comes forth a young, new Official - Houjou - who challenges the corruption. Gifted by the Emperor with three beheading devices, he is charged with bringing justice back to the courts.

Based on the historical figure of Justice Bao (Chinese reading of the name), who was said to be an incorruptible official, this is a light-hearted romp through ancient China as he and his assistants work against the corruption that has become the norm in the Imperial Courts.

For more on the historical person and legends surrounding him, see:
http://en.wikipedia.org/wiki/Bao_Gong

One of Go Nagai's first works, this violent period piece takes place in the 1500s and stars a talented, low-ranking ninja named Shishimaru. In it, Shishimaru fights against Ginnai Doma (an immortal samurai who, despite being butchered multiple times, doesn't die) because Ginnai murdered his comrades.

Despite being set in historical times, it has time travel, aliens and the alternate universe war.

During the second half of the 19th Century, Europe became fascinated by Japanese culture. A young Japanese girl named Yune travels to France, where she starts working in a shopping arcade in Paris at a crafts store called Enseignes du Roy. She and the store owner named Claude cooperate with one another in order to get over their cultural differences. This is the story of Yune's stay in Paris.

Imagine living in a town where supernatural beings stalk the night for their next prey. Toukei Ibun takes place 29 years after Tokyo was established as the capital of modern Japan. Manzou is the owner of an inn in the town of Asakusa. His friend Hirakawa is a journalist who is investigating the bizarre crimes that keep occurring all over the city in the dead of night.

In a world where dangerous aberrations lurk outside the walls of the last human refuge, Piras, the spoiled and immature son of a war hero, must recover his identity after being classified as a terrorist and hunted down by a corrupt empire. Awaken is an ongoing webcomic.

Born only a reunion with you...
300 years ago, peony flower essence
Lover's heart to find the reincarnation of
Fallen and Qiu Shui
Of time, unrequited love
Soul-stirring, touching and tempting...

Luo'Hua was found under a Mu Dan Blossom Tree as a baby, and taken in by a man where she joined his family. The man's wife regards her as her husband's child out of wedlock (and a curse that made their beautiful flower garden die), so Luo-Hua lives her life suffering because of these assumptions, and her only friend is her stepbrother, Yi Qing. As a teenager, Luo'Hua is taken in as a servant in the Gui household to repay her family's debt to the Gui family, and finds herself among much conflict as she's assigned to deliver the young master's clothes and meals under the Gui Madam's schemes.

From The Zero Alliance:
Every ten years, a young woman is offered as a sacrifice to the mountain god.
When the tengu goes to see the sacrifice, he finds out that the sacrifice actually volunteered for the role.
And the sacrifice turns out to be a young boy.