Buffalo Castle was a gamebook

Gamebook

A gamebook is a work of fiction that allows the reader to participate in the story by making effective choices. The narrative branches along various paths through the use of numbered paragraphs or pages...

 first published by Flying Buffalo

Flying Buffalo

Flying Buffalo Incorporated is a Scottsdale, Arizona game company that publishes role playing games, card games, gaming materials, and runs Play-by-mail games....

 in 1976 (ISBN 0-940244-01-2).

Although it is widely believed that the Fighting Fantasy

Fighting Fantasy

Fighting Fantasy is a series of single-player fantasy roleplay gamebooks created by Steve Jackson and Ian Livingstone. The first volumes in the series were published by Puffin in 1982, with the rights to the franchise eventually being purchased by Wizard Books in 2002...

 series of books were the first gamebooks to use dice and allow the character to possess statistics and equipment, Buffalo Castle pre-dates the Fighting Fantasy series by six years and used the same types of mechanics. Buffalo Castle may have been the first published adventure gamebook http://gamebooks.org/show_item.php?id=2703

Using the Tunnels and Trolls

Tunnels and Trolls

Tunnels & Trolls is a fantasy role-playing game designed by Ken St. Andre and first published in 1975 by Flying Buffalo. The second modern role-playing game published, it was written by Ken St...

 role-playing system Buffalo Castle consisted of 150 paragraphs in A4 format. The story was primitive in comparison to later gamebooks and has been described as a dungeon crawl

Dungeon crawl

A dungeon crawl is a type of scenario in fantasy role-playing games in which heroes navigate a labyrinthine environment, battling various monsters, and looting any treasure they may find...

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