The game is named after two rivers in the region we now call the Middle-East. The rivers together formed natural borders for an area which harboured several grand ancient civilizations, including Sumer, Babylonia, Assyria. The Greeks called this area Mesopotamia, which literally means "between the rivers".
Game references to this period, imagery as well as rules, are superficial and hardly relevant for game play. Just like chess does not have much to do with medieval knighthood.
The game can be played by 2,3 or 4 players. The gameplay falls somewhere between tactical and strategical. As with many games the short term objectives gain prominence when more players participate, as each player's chance to follow up on his or hers previous moves becomes less likely. Luck plays a role, but is seldom decisive. No dice are thrown, cards (board tiles) are taken face down from a stock.
During the game each player collects coloured tokens in a variety of ways. Tokens come in four colours. After the final round each player sorts his or her tokens by colour. Players then compare the size of their smallest colour set.
Example:
John has 6 black, 8 red, 12 yellow and 12 blue chips.
Mary has 9 black, 10 red, 6 yellow and 15 blue chips.
Kurt has 14 black, 14 red, 5 yellow and 20 blue chips.
Though Kurt has lots of blue chips this is not relevant at all. His smallest set is only 5. Therefore Kurt finishes third. John and Mary both have a smallest set of 6 chips. Therefore the one but smallest set decides the game. Mary wins.
This is one of the fun aspects of the game. An inexperienced player is easily seduced to focus on quasi profitable moves which provide several chips in one go, but with a colour that he or she has already in ample supply.
The game starts with ten isolated tiles already placed on the board. Player put tiles, which come in four colours, next to a tile which is already there. In this way single tiles grow into small tiled regions.
Each player has four figures that can be placed on the board in stead of and next to a tile: king, priest, merchant, warrior. Similar figures can not coexist in the same region. A player can contest a region by placing a figure in an area that already contains a figure of that kind. This is called an internal conflict. The position of each figure on the board, in combination with cards each player puts on the table, decide which figure is ousted and who gains a few chips.
Sooner or later tiled regions will grow towards each other until someone places a tile that merges two regions into one. The new region may now well contain several incompatible figures. This time we speak of an external conflict. Now different rules decide who wins.
This description of the rules is not exhaustive, but hopefully gives a first impression of what kind of game Euphrat und Tigris is. A player will want to establish and enforce positional advantages and prepare timely takeovers in order to gain points.
Euphrat und Tigris was released in the United States of America by Mayfair Games, under the title Tigris and Euphrates.
Another review can be found at http://boardgames.about.com/library/games/bleu01r1.htm