Perudo, also known as Bluff or Liar's Dice, is a simple dice game for up to six people, which is based on an ancient Peruvian pastime with similar rules. It was brought out by University Games in 1994, with some question as to whether they had plagiarized the earlier (1987) Liar's Dice game by MB. Each player has five dice and a cup at the start of the game - if you buy the Perudo box set in a shop then the dice will be brightly coloured, with special symbols instead of the '1', and matching bright plastic cups, but Perudo can just as easily be played with ordinary dice and any small, non-transparent receptacle, such as a mug.

The game is round- and turn-based, with players rolling dice to see who begins the first round. Once the round begins, all players shake their dice in their cups, and then slam their cups face down on a table or the floor with their dice concealed beneath. Each player carefully looks at their own dice, and the bidding round commences.

The rules for bidding are as follows:

• The aim of the bid is to guess the total amount of any single die face (Ace, 2, 3, 4, 5, 6) in all the dice in the round combined.
• Aces (1s) can count either as themselves or as any other number.
• Bids must always rise, i.e. if the player to your left bids "Five twos" then you must either bid a higher number of twos, or five (or more) of a higher number, e.g. "five threes".
• When making an aces bid, the number is doubled - i.e. if someone bids "three threes" then you can bid "two aces", because that counts as four of any other number. "Two aces" must be followed by a bid of "three aces" or higher, or "Five twos" or higher.
• The alternative to making a bid is to challenge the previous bid.
• If a player wants to challenge any bid, he or she announces "Dudo!" and all dice are revealed. If the bid is incorrect (e.g. if the bid was "eight threes" and only seven threes and aces are showing) then the bidder has to sacrifice one of his or her dice. If the challenged bid was correct (if eight or more threes and aces were showing) then the challenger must sacrifice one of their dice.
• Special rules apply to a 'Palefico' round in which the bidding is begun by a player with only one die left - the bidding is 'fixed', which means that aces only count as ones, and it is not possible to switch suit - if the Palefico player bids sixes, then all subsequent bidding must stay on sixes. This gives a small advantage to the Palefico player, as otherwise the handicap of only having one die is impossible to deal with.
• A new round begins after each challenge, and the winner is the last person left with any dice.

As you might imagine, Perudo contains a substantial element of bluff and psychology, which makes it an extremely popular party game in the UK. All the elements of bluff are possible - you can mislead people with your first bid into thinking that you have many dice of one value, and then switch to another value, hoping that they will challenge; you can start high in order to catch another bidder out later on; you can heckle a player who is trying to decide whether to bid or challenge; you can act nervous, or act confident. Some players tend to stick to reasonable estimates for their bids, while others tend to bluff a lot more. All these elements will be familiar to players of card games such as poker or bridge, and it is no surprise that Perudo can be played as a gambling game. It's related to Yahtzee, but simpler and more elegant in concept, and with more psychologically complex gameplay - much the same relationship as exists between, for example, Risk and Diplomacy.

I've played plenty of Perudo, after being introduced to it by a group of jugglers in Leeds. They followed the above rules but with variations and conventions of their own that had built up over a couple of years of parties and lazy afternoons. For example, the Palefico round had become the 'Pornifico' round, and all players had to simulate a porn star moustache by holding their index finger across their upper lip for the duration of the round. It made sense at the time.

Order Perudo online: http://www.amherstlodge.com/games/perudo/perudo.htm