How and when to use 形（かたち、けい、かた）


What exactly are the scenarios where かたち、けい or かた would be used? For example,
in this sentence 「 輪の形に動かす」, is it かたち or かた？




かたち and かた are different, though related, words.

かたち is the more common and general-use of the two, and corresponds fairly
closely in meaning to the English word "shape", referring to the basic outward
appearance of something, often in a 2D rather than a 3D sense. When you see 形
used on its own, it's generally safe to assume that かたち is the intended
reading unless you have reason to think otherwise, and this includes your
example sentence.

かた is a somewhat more technical term, and usually refers to one of a few
different defined forms or types of something. In most of its uses, it's more
commonly written with the kanji 型 than 形, though they can be interchangeable.
It's also much more common than かたち in kun-reading compounds, particularly in
its usage as a suffix meaning "shaped like X" (usually pronounced ～がた due to
rendaku, eg. 菱形{ひしがた} "diamond-shaped", 卵型{たまごがた} "egg-shaped").

けい is the on-reading of the kanji, and to my knowledge it's not generally used
as a word on its own. Like most on-readings, it largely occurs in Sino-
Japanese compound words (kango).




かたち and かた are different, though related, words.

かたち is the more common and general-use of the two, and corresponds fairly
closely in meaning to the English word "shape", referring to the basic outward
appearance of something, often in a 2D rather than a 3D sense. When you see 形
used on its own, it's generally safe to assume that かたち is the intended
reading unless you have reason to think otherwise, and this includes your
example sentence.

かた is a somewhat more technical term, and usually refers to one of a few
different defined forms or types of something. In most of its uses, it's more
commonly written with the kanji 型 than 形, though they can be interchangeable.
It's also much more common than かたち in kun-reading compounds, particularly in
its usage as a suffix meaning "shaped like X" (usually pronounced ～がた due to
rendaku, eg. 菱形{ひしがた} "diamond-shaped", 卵型{たまごがた} "egg-shaped").

けい is the on-reading of the kanji, and to my knowledge it's not generally used
as a word on its own. Like most on-readings, it largely occurs in Sino-
Japanese compound words (kango).

