Historically keno originated in ancient China and was used to generate funds to finance the building of the Great Wall of China and also to finance wars. One can imagine the kind of “house edge” that the keno game must have had at that time. However modern-day online keno games are not that bad. They generally have an average payout percentage between 92% and 96%, which makes them somewhat worse than online slot games in this regard. Therefore the first policy that keno players must adopt is one of wagering limited amounts on this game.

All online keno games appear alike. Players mark off between 1 and 15 numbers on the grid. Then 20 balls are drawn at random. Players are paid out on the basis of how many of the 20 drawn balls had numbers matching with the numbers marked by them. So far the keno games appear similar. The difference lies in the nature of the payouts. Generally there are two types of payout tables. One can be termed as conservative and the other as aggressive. In the conservative table the payouts start with even very few matches, but the payouts do not rise to phenomenal levels. In the aggressive payout tables the payouts begin at about 50% of the numbers matching, but they payout phenomenal amounts. For example, the Microgaming online keno pay table is a conservative one. For 15 numbers marked on the grid the payout begins with 3 matches paying 0.5 coins and 15 matches paying 10,000 coins. In contrast the Realtime Gaming online keno pay table is an aggressive one. For 15 numbers marked on the grid the payout begins with 7 matches paying 12 coins and 15 matches paying 100,000 coins. One way of looking at this is how much risk the player is willing to take for what kind of return. If the player is not satisfied with conservative returns and is willing to take high levels of risk then he may prefer the aggressive payout table. On the other hand a risk-averse player who is satisfied with conservative returns would prefer the conservative payout table. However the risk-taking player should know what level of risk he is taking. The average payout ratio of the conservative table is 95.2%, whereas the average payout ratio of the aggressive table is 84.4%. This is a huge difference. Another problem with the aggressive table is that there is usually a cap on the maximum payout as expressed in credits. Therefore players who wagered large amounts may not be able to cash the complete payout as expressed in coins. Aggressive players need to check out this very carefully in the online keno game they are playing.

Another issue that keno players have to resolve is how many numbers to mark on the grid. One can easily understand that the more numbers the players mark on the grid the greater the chances of at least some of the numbers matching with the balls drawn. However this means larger wagers. Fortunately it is possible to calculate the average payout ratios in each case. In the Microgaming payout tables the average return for 3 numbers marked on the grid is 93.0%. For most numbers the average payout varies between 93% and 94%. However for 14 numbers and 15 numbers marked on the great the average payout increases to above 95%. For 7 numbers marked on the grid average payout is 96.4% and for 13 numbers marked on the grid the average payout is 96.5%. Hence serious keno players should mark out 13 in numbers on the grid because it gives them the greatest return.