Stories about kingdoms
 

Hi.
I need recommendations. It could be anime, manga, or light novel. I'm searching for something that shows a lot about how to build and manage a kingdom, the lives of the people, the politics in the government, and the changes that occur in a kingdom (such revolution, rebellion, major disasters, etc.).
It may fulfill one or more of the criteria mentioned above.

Thank you.

Maoyuu Maou Yuusha is probably the closest thing you'll get. A Demon Lord who seems to have a degree in economics, and her plans to end a never-ending war with the help of her favorite hero. It's an online novel which became so popular it got published and spawned a bunch of manga adaptations. Look for the series' thread in our manga subforum for a helpful pic-by-pic comparison of the manga versions -- though really only one "full" series (+a funny little 4koma) is being regularly translated right now.

It doesn't start off about this, but as a whole it's a very large element of Juuni Kokuki/The Twelve Kingdoms.

Maybe you could try Dog Days : it implies the battle between two kingdoms while the protagonist is coming to the rescue and protect the princess of one of these kingdoms.

You could also try Koihime Muso, consisted of 3-season and 12 episodes each. The story is a retelling of the Three Kingdoms, except that the characters are gender-bended as females.

Utawarerumono I suppose.

Wow, some great suggestions are above already. I’ll add some, these anime are also about kingdoms (more or less), not in order:
Yokoyama Mitsuteru Sangokushi (manga & anime)
Kyo Kara Maoh! (light novel, anime & manga)
Sengoku Basara (two-season anime & game)
Utawarerumono (anime & game) - I got ninja'd again by jedinat :heh:
Ryuuroden (manga)

Personally I'm enjoying the new version of Three Kingdoms, a chinese live-action TV series.

There are a billion other adaptions of Romance of the Three Kingdoms too, even anime.

Saiunkoku Monogatari is set an a faux-Chinese imperial court; it has a lot of political drama. The show is in licensing limbo at the moment, so it's a bit hard to find.

Court politics play a role from time to time in Seirei no Moribito as well. it's less apparent in the same author's Kemono no Sou-ja Erin, but still there. (Uehashi's novels, from which these shows are adapted, focus on founding myths and how they influence the modern politics of empires.)

Another strong endorsement for Twelve Kingdoms.

The currently-running Hyouge Mono recounts the events of the Sengoku period when Nobunaga Oda began the process of unifying Japan's decentralized feudal structure. Only eleven of the thirty-nine episodes have yet been subbed, and they're being released at a very slow pace. I'd keep an eye on it though, or just watch the episodes as they are released as I do.

Thinking about it now, it did have a fair bit of that during the story, so I'll second it.

Thirding. I think it's the best series that meets your needs here.

I thought I might be the first to suggest this one, but you beat me to it :)

There are a number of interesting themes with this series. The protagonist is a woman who is trying to enter the male-dominated government. She befriends a number of people along the way, including the emperor. That relationship provides some interesting insight into what it might be like to be the head of a large country that is divided into various provinces, each with their own government officials and "elite" family clans. An arc of the story also focuses on events at the level of a province far away from the capital city.

Overall I think it fits what you're looking for, and the characters are fantastic. I just wish they'd make a third season already...

Utawarerumono
Jyu Oh Sei - had kingdoms known as rings i guess
Break Blade
Tears Of Tiara

Oh yes, I forgot to mention any anime setting in Warring States period and tells the life of warriors in this era. Examples : Sengoku Basara, Sengoku Otome, Sengoku Strays (yeah it's a manga)...