Game concept · All Under Heaven
Japanese Manor
The game also links it as Japanese Manors, Manor, Manors, Shōen, Family Manor, Family Manors.
From the game's encyclopedia
A Manor - or Shōen - is a type of Domicile held by the House Head of notable Noble Families within Ritsuryō and Sōryō Realms. They represent private landholdings untied to any particular Landed Title.
Japanese Manor Building may be constructed here to expand the family's wealth and Influence, and the Manor will be inherited by future generations.
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.
Japanese Manor is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "A Manor - or Shōen - is a type of Domicile held by the House Head of notable Noble Families within Ritsuryō and Sōryō Realms." It is part of Domicile. The game also links it as Japanese Manors, Manor, Manors, Shōen and 2 more. 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.