7 books
The Tortoise Tale Niki the Tortoise and the Ghost King How Niki Fed the Village
The Tortoise Tale Niki the Tortoise and the Snail How the Snail Married the King's Daughter
The Tortoise Tales Niki the Tortoise and the King's Wife
The Tortoise Tales Niki the Tortoise and the Falcon
The Tortoise Tales Niki the Tortoise and the Squirrel
The Tortoise Tales Niki the tortoise and the birds
The Tortoise and the Pig