Tanno Tanta is the bravest boy in Kurinoki-machi (“Chestnut Town”). On Tanta’s fifth birthday, a white envelope lands at his feet. Inside the envelope, Tanta finds an “expedition map,” and immediately sets out to see what awaits him there. He buys a leather hat at the hat store, a snack at the candy store, and a telescope at the toy store before setting out on his journey.

Tanta marches along, loudly chanting, “I am Tanno Tanta, chief of the Lion Mountain adventurers.” Before long, he meets a leopard cub. “Hey, you!” he calls out to the cub. “Are you with me?” The cub immediately answers, “I am,” and introduces himself as Baribari Barihi. He was actually the one who sent Tanta the map, wanting to celebrate the boy's birthday.

Soon becoming fast friends, Tanta and Barihi enter a dense, dark jungle. Chanting “Now for a jungle expedition. It’s not scary, because we’re not alone,” they make their way through the trees to arrive at . . . Barihi’s house!

The reader of this book all but becomes Tanta, examining the map, making preparations, and striding through the jungle with Barihi. Children are sure to love every moment of Tanta’s excitement-filled fifth birthday. Each page has vividly colored illustrations by Yamawaki Yuriko, enriching and broaden the world of the story and further feeding the reader’s imagination. The map on the flyleaf is also essential.