Total War: Shogun 2 - Fall of the Samurai: The Saga Faction Pack

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

The Saga Faction Pack adds a new playable faction to Total War: SHOGUN 2 - Fall of the Samurai, previously only available in the Limited Edition, for use in single or multiplayer Campaign modes and Custom and Multiplayer Battles.
Centuries of trade with outsiders has given the people of Saga an understanding of foreign and modern ways, allowing them to adopt new military technology quickly.

Faction Traits:

Gunnery (+5 to the accuracy of all artillery pieces)
Industry (+5 to growth from industrial buildings)
Engineering (-15% reduction to the recruitment and upkeep costs of ships)
Rangaku (Trade with the Western Powers has been established)

History of the Saga

The Modernisers

The Saga domain is ruled by Nabeshima Mochizuru, the latest in a line of daimyo who were given this territory after the Tokugawa won the vicious civil war of the Sengoku Jidai. The Nabeshima did well by being sensible enough to join the Tokugawa cause while there was still some doubt over the result. They did not wait until the Battle of Sekigahara to decide where their true loyalties lay.
The domain includes the port of Nagasaki, a valuable resource for any daimyo. It is here that Japan has its only official trade with the West, and it is here that interesting ideas arrive in the country. Perhaps this knowledge of the harshness of the outside world is what has convinced the Nabeshima to throw their weight behind the Imperial Court rather than the Shogun.
The Nabeshima clan can rely on a few advantages in the coming struggle: they have Western connections and trade that is far ahead of any other domain. In turn, this learning allows them to be artillery experts, and have good shipbuilding and industrial facilities. The modern world has much to offer to those who would embrace it. Interestingly, the historical Nabeshima Mochizuru eventually resigned his position and left Japan to study in England.