Ranma ½ - Season 1 - Eps 158: A Ninja's Dog Is Black and White
Ryoga encounters Checkers (Shirokuro) a black and white dog. The dog saves P-chan when they went over a waterfall, so Ryoga starts to take care of the dog and feed it. The dog takes a love letter Ryoga had written out of his backpack and delievers it to Akane. Akane doesn't know who the letter is from because Ryoga didn't sign it, but gives Checkers a letter to give to return. The letter said that she had someone that she loved, and was sorry she couldn't return the writers feelings. Ryoga is horrified when he reads this, but then Ranma asks him if he had signed the letter Akane read. Upon realizing that he hadn't, Ryoga believes that the 'somebody' Akane is talking about is actually him.
About Ranma ½

Title: Ranma ½
First Air Date: 1989-04-15
Last Air Date: 1992-09-25
Status: Ended
Rating: 8.6/10 (from 1421 votes)
Language: JA
Seasons: 2
Total Episodes: 161
Network: Fuji TV
Genres: Comedy, Action & Adventure, Animation, Sci-Fi & Fantasy
Production Companies: Studio Deen
Synopsis
Ranma Saotome, a teenage martial artist, and his father Genma travel to the 'cursed training ground' of Jusenkyo in China. There, despite the warnings of the Chinese guard, they fall into the cursed springs. From now on, whenever Ranma is doused in cold water, he turns into a girl and a cute, well-built redhead at that. Hot water changes him back into a man again, but only until the next time. To make matters worse, his father engages him to Akane Tendo, a girl who hates boys.
Cast

Kappei Yamaguchi
Ranma Saotome ♂ (voice)

Megumi Hayashibara
Ranma Saotome ♀ (voice)