Shirokuro, also known as Checkers, is Ryoga Hibiki's pet dog. Half black, half white, the name "Shirokuro" can broken down into "shiro" meaning white and "kuro" meaning black, which is why it is translated "Checkers" in the English dub.
Shirokuro and her puppies are the only members of the Hibiki family who actually live in their home full time. A clever canine, Shirokuro is able to live all by herself for long periods of time while keeping the house clean and her puppies safe. She also holds the distinction of being the only member of the family with any sense of direction at all. Additionally, she can recognize Ryoga as both a human and a pig.
One day Akane, Nabiki, Kasumi and Ryoga (in his cursed form) are watching TV when a dog named Shirokuro Hibiki, appears and the presenter explains that she's like her master to come home and see it's new puppies. After trying to get to his house with Ranma Saotome, Ryoga falls into a river and turns into P-Chan. When P-Chan finds Akane Shirokuro appears. Shirokuro then hugs P-Chan and carries him away back to Ryoga's house. As Ryoga meets up with Yoiko (who is actually Ranma in disguise) Akane talks to Shirkuro about how she's had a lot of puppies.
After a little dispute between "Yoiko" and Ryoga, Shirokuro joins them with Akane in Ryoga's room where she sits and watches them play a card game, she then tries to eat something out of a little bag on Ryoga's bed after he deals with "Yoiko". All three of them then take Shirokuro for a walk, where she along with Ryoga and Akane try to find "Yoiko" who has run off. After "Yoiko" has run out of sight of Ryoga, Akane and Shirokuro, she along with Akane try to comfort Ryoga (with Akane trying to tell Ryoga that "Yoiko" is most likely at home while Shirokuro simply pats her paw on his back). Suddenly, Shirkuro sees "Yoiko" and chases her, Ryoga then hugs "Yoiko" with great relief while Shirokuro holds onto one of her puppies (that "Yoiko" found after she'd ran away from Ryoga).
In the anime, Shirokuro is a male dog who was born in Sarugakure Village and was trained in the art of the "Ninken", or "Ninja Dog". However, one day Shirokuro decides to leave the village and becomes a "fugitive canine" and so is chased wherever he goes by a pack of other "Ninken". Ryoga, who is travelling on his own again, comes across a rapid flowing river and decides to stop and have a drink. When Ryoga is about to get some water he looks up and sees Shirokuro being carried away by the river. At first Ryoga mistakes Shirokuro for a raccoon but quickly realises that it is a dog.
Ryoga decides to save the Shirokuro by jumping onto a log and having Shirokuro grab onto his Umbrella. However, Ryoga gets splashed by the water in the river and so turns into a pig. After both Shirokuro and Ryoga fall off a waterfall at the end of the river, Shirokuro licks Ryoga until he awakens. Once Ryoga has turned back into his human form, Shirokuro notices a letter in Ryoga's bag. After Ryoga tells Shirokuro that the letter is for Akane and tells about his true feelings for her Shirokuro decides to take the letter to the Tendo Dojo.
Shirokuro arrives at the Dojo the next morning, disrupting Ranma and Genma's training in the process. When Kasumi notices the letter in Shirokuro's mouth is addressed to Akane she gives it to her. After Akane has written a reply she gives to Shirokuro to give back to the sender. However, during this time Sasuke has realised that Shirokuro is a "fugitive canine" and has a reward for his capture. Sasuke tries several times to capture Shirokuro but fails on every attempt. Sasuke then instructs Ranma to follow Shirokuro, Ranma does as instructed and while he follows Shirokuro he sees a small child being scared by another dog, however, before Ranma can react Shirokuro headbutts the other dog and scares it away, this leads Ranma to believe that Shirokuro isn't a bad dog after all. Meanwhile, Kasumi tells the others at the Tendo Dojo that she's named the dog "Shirokuro" because of it's coloration.
After continuing to follow Shirokuro, Ranma finds that Shirokuro is outnumbered by a pack of other "Ninken" and as Shirokuro is holding Akane's letter he can't bite the other dogs. When it looks like Shirokuro is about to lose, Ryoga appears and uses his "Bakusai Tenketsu" technique and scares the pack away. Shirokuro then gives Ryoga Akane's letter. Ryoga reads the first two sentences and believes this shows she loves him, however, when he reads on he realises that Akane says that she "loves someone else". Ryoga is very upset by this, then Ranma explains that the letter is addressed to "Mr. Unknown" so Ryoga must have forgotten to write his name on the letter. This news overjoys Ryoga who decides that Akane could still be in love with him. Ryoga then leaves with Shirokuro, while Sasuke burns the Wanted scroll about Shirokuro.
- In the anime Ryoga never actually gave Shirokuro a name, as "Shirokuro" was given by Kasumi.
- Shirokuro also appears in the Ranma Hot Songs contest.
- The female Shirokuro and her puppies show up during the chase sequence in Big Trouble in Nekonron, China, laying on top of the Dojo Destroyer.
- Shirokuro has Chimerism.
- Awoo - Shirokuro communicating in the manga.