Shiba Inu is puzzle 4-B in easy mode of Picross 3D. It is also found on the back and front covers of the game, and is probably the most famous puzzle in the game.
"This breed is very popular in Japan. When its population dipped to dangerously low levels, a law was passed to protect it."
On the front cover of Picross 3D, in the bottom right corner, the Shiba Inu puzzle's shape can be found, and below it a question asks "What's this shape? (see reverse)". On the back cover, it tells the answer and says "It's a dog!" instead of calling the puzzle a Shiba Inu.