In One Piece for example I've noticed that the word Log Pose is written as 記録指針｛ログポーズ｝. Another example, also found in One Piece, is the word Poneglyph, written as 歴史｛ポーネ｝の本文{グリフ｝. Why do words such as these have their own kanji readings despite being loanwords or katakana words? I believe I've seen a similar case in JoJo's Bizarre Adventure manga but I cannot recall which word.

In One Piece for example I've noticed that the word "Log Pose" is written as 記録指針｛ログポーズ｝. Another example, also found in One Piece, is the word "Poneglyph", written as 歴史｛ポーネ｝の本文{グリフ｝.

Why do words such as these have their own kanji readings despite being loanwords or katakana words?

I believe I've seen a similar case in JoJo's Bizarre Adventure manga but I cannot recall which word.

In One Piece for example I've noticed that the word Log Pose is written as 記録指針｛きろくししん｝ with ログポーズ as furigana. Why does Log Pose have it's own kanji despite being a loanword? I believe I've seen a similar case in JoJo's Bizarre Adventure manga but I cannot recall which word.

In One Piece for example I've noticed that the word Log Pose is written as 記録指針｛ログポーズ｝. Another example, also found in One Piece, is the word Poneglyph, written as 歴史｛ポーネ｝の本文{グリフ｝. Why do words such as these have their own kanji readings despite being loanwords or katakana words? I believe I've seen a similar case in JoJo's Bizarre Adventure manga but I cannot recall which word.