Game concept · All Under Heaven
Ritsuryō Government
The game also links it as Ritsuryō.
From the game's encyclopedia
Ritsuryō is a type of Bureaucratic Government unique to Japan.
It is a centralized Bureaucratic Government Form where Characters are appointed as Governors on behalf of their Liege, have access to Influence, and Noble Family Heads have a Family Manor and House Aspiration.
A Kampaku governs the Realm on behalf of the Japanese Emperor, and may be elected from among Noble Family Heads, or imposed by Faction demand.
Ritsuryō Vassals generally govern only a single County, but may reject the centralized system and become local Sōryō lords to build their own power, though this is usually considered a Criminal act.
Ritsuryō House Heads may create and join House Blocs within the Realm, which will support the Leading House in becoming Kampaku.
Japanese Governments have a lower Domain Limit than others, which may be increased by upgrading the Family Manor.
The Ritsuryō system refers to the centralized administrative government of Japan, inspired by the Chinese Confucian bureaucracy.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Ritsuryō Government is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "Ritsuryō is a type of Bureaucratic Government unique to Japan." It is part of Government. The game also links it as Ritsuryō. Patch 1.20.1.2, from game/common/game_concepts/tgp_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/tgp_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.