Kazu (かず Kazu) is Shizuka's cousin. He appeared in the 1979 anime episode My Train Set. He is from Hokkaido and was visiting Shizuka in Tokyo when he ran into Doraemon and Nobita who helped him when he was injured and took him back to Shizuka's house.
Kazu is basically Shizuka but with no pigtails.
Kazu is very interested in trains and is always taking photos of them, especially electric trains. He has a photo of himself standing in front of his favourite train which he accidentally leaves behind in Tokyo, but is returned to him by Nobita and Doraemon.