Board Thread:News and Announcements/@comment-26581304-20150906194347/@comment-1577342-20150914010507

Yes, it is always a better idea to breed a target rare + target normal when breeding for any given target, as this produces the best overall chance of obtaining a rare. I listed the other cases because you implied that there are different "best" strategies based upon the different possible programming alternatives.

By definition, the likelihood of hatching a Rare is always going to be less than 50%. Regardless of whether the actual percentage is applied to a 1-100 range of all possible outcomes, or the game checks to see if the Z4 you got is a Rare variant after determining IF you got a Z4, there is no difference in the optimal strategy.

The X1 + Y3 option discussed CAN and does produce both Z4's and Rare Z4's. It simply is less likely to do so than the optimal Rare Z4 + Z4 strategy.

To summarize for all, the possible methods for breeding a Rare Z4 are three, from most probable, to least:

Rare Z4 + Z4: This relies on a failed breeding, but will always net a Z4. This is most likely produce Rare Z4's at, on average, the actual percentage of Rare Z4's vs normal Z4's set by BBB

X1 + Y3: This requires a successful breeding, meaning that the possible outcomes are X1, Y3, Z4, and Rare Z4. This strategy is preferable to the next strategy because a failed result of X1, the 1-element parent breed, will take less time to clear the way for another try. In theory, the fact that a 1-element failure result is much more likely than a 3-element failure result will make up for the longer time required from the occasional 3-element failure.

X2 + Y2: This requires a successful breeding and has no advantages over other methods, except possibly earlier availability.