Optimal Tyranu Evavu

The basics

The objective of Tyranu Evavu is to guess whether the next card in the pack of cards will be higher or lower. If you guess correctly, then you keep guessing and try to get as long a streak as possible.

In Tyranu Evavu, aces are high. For those of you that don’t know what that means, the cards run as follows from lowest to highest:

2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King, Ace

One of the first things you will notice is that as the natives speak Tyrannian not English, their buttons are also not in English. If you think the next card is higher, then press “Tyranu” and if you think it is lower, “Evavu”. The second thing to point out is that those Tyranu and Evavu buttons move position randomly, so double check each turn that you are pressing the correct button; it’s very annoying to mess up a long streak because you pressed the wrong button. If the card is the same value as the previous one, then you win no matter whether you called higher or lower (such generous Tyrannians; it could have been a loss if they had felt like being meanies).

As with most games in Neopia, if you can score high enough (which in this game means a very long correct guessing streak) there is a trophy available. You have to be in the top 17 when trophies are handed out towards the end of the Neopian day. There is also an avatar available for this game, but I’m not going to tell you how many you need to get because those clubs the dealers carry around look mighty heavy and I don’t want to get on their wrong side!

It costs 30 NP to play a game and the winnings are as follows:

You really aren’t going to earn a lot of neopoints playing this game unless you are extremely lucky. The odds are not that great and the prizes not that big. Most people play for the avatar, a trophy or fun.

Optimal play

The tactics seem obvious. If you get a low card, then guess the next one will be higher (Tyranu); if you get a high card, then guess lower (Evavu). Well, yes, fundamentally this is true, but we can improve our odds, particularly as the game progresses.

In the pack there are 52 cards, 4 suits (diamonds, hearts, clubs and spades) and 13 different cards in each suit. At any point in the game, we want to know how many cards are higher or lower than the current card, which means we have to keep track of what cards have been played.

For example, a game starts and the first card is 8 clubs. This means there are 24 cards that are lower (2, 3, 4, 5, 6, 7 in all suits) and 24 cards that are higher (9, 10, J, Q, K, A in all suits) and 3 that are the same as my card (8 of diamonds, spades and hearts).

If I guess lower, my chances of being correct are:

Cards that are lower: 24

Cards of the same value: 3

Total cards left to play: 51

Chance of guessing correctly: (24+3)/51 = 52.9%

If I guess higher, my chances of being correct are:

Cards that are lower: 24

Cards of the same value: 3

Total cards left to play: 51

Chance of guessing correctly: (24+3)/51 = 52.9%

In other words, it makes no difference what I pick; the chances are the same. Not terribly helpful at this point, I admit, but let’s now imagine I have managed to get 12 cards in and have played the following cards so far:

• 8 clubs
• 9 hearts
• 2 diamonds
• 2 hearts
• 3 hearts
• 4 hearts
• 4 clubs
• 6 spades
• 6 diamonds
• 6 hearts
• 7 hearts
• 9 spades

So I have a 9 of spades. If you ignored the cards that have been played so far, you would say there are 28 cards that are lower, 3 the same and 24 higher, so would choose lower or Evavu.

However, because we have been keeping track of the cards, we know this isn’t correct. There are actually 18 cards lower than a nine, 2 cards are the same value and 20 are higher. We should pick higher or Tyranu and improve our odds to 55% from 50% if we had chosen Evavu.

It's not the greatest increase in chances, I accept, but the further into a streak you get, the more useful it is to know what has been played as you find yourself hovering over a 6 or a 10, uncertain what to do.

The above simply maximizes your chances of getting it right and my personal view is why would you not want to do that? The obvious answer to why not is it takes too long, but I have a solution and it’s a very simple spreadsheet.

You need to create a grid with a row for each card type and then columns for the number of cards played, number of cards left, the number of cards above that value and the number below. You will need to add some simple formulae:

The # Left column has a formula in it which is 4 - # played for that row.

The Above column is the sum of the number of cards left for that card type and any higher.

The Below column is the sum of the number of cards left for that type or lower.

It should look something like this:

As you play, you simply add 1 into the correct # Played cell. So if the next card was a 3, then I would put a 1 in the # Played cell next to 3. If the card after that was a 9, I would change the cell in the 9 row to a 2.

As you do this, the number of cards higher and lower than each card number will keep recalculating and you pick the option with the most cards. If you want to get clever, add percentages and conditional formatting to see odds and see more clearly whether to go higher or lower. You don’t need to, though; the above will do.

If you guess incorrectly, clear the cards played column and start again. Have the spreadsheet on part of your screen next to Tyranu Evavu and it’s very quick to update as you go along.

So armed with our spreadsheet and maximizing our chances of guessing correctly, it is just a question of playing over and over again until you get the score you want. It is important to note, the above simply maximizes your chances of guessing correctly, but this is very different from being able to guess correctly all the time. You do need a lot of luck, especially early in the game whilst you have nearly a full pack in play. Just keep playing and it should eventually come good, although if the Tyrannian dealers think you have played too much, they will ban you for the day. Don’t expect to sit down and do a marathon several hour session; you will be kicked out long before that. Good luck!