Guide to shiny breeding mechanics in Gen 2

I couldn't find many other guides go in depth for shiny breeding in the gen 2 games so I decided to write a quick guide for myself or for anyone interested.

1: Misconceptions

There is a quite common idea that shiny breeding only works if one of the parents are a shiny pokemon. This is partially right but what matters is that some of the DVs(Determinant Values. Basically the same as IVs but range from 0-15) of the parent needs to be a specific value.

Another misconception is that the odds of finding a shiny in an egg can be raised to 1/64, this is true but this case will only apply if the pokemon being bred has a 1/8 chance of being male or female or the parent with the shiny genes is a Ditto.

2: How DVs are passed down

When an egg is created it will generate its DVs determined by the parent of the opposite gender. There are only 5 DVs in gen 2, but we can ignore HP as its generated differently to the other DVs. That leaves us Attack, Defense, Special, and Speed.

• The Attack value is randomly generated but it will determine the gender of the pokemon dependent on the species gender ratio. This will affect how likely you are going to get an opposite gendered child from the parent with the shiny genes and can affect the chances of getting a shiny egg.

• The Speed value is generated at random and can be ignored as it won't affect the chances in any way.

• The Defense value will be passed down from the opposite gendered parent or ditto.

• The Special value will be passed down from the opposite gendered parent or ditto half of the time or be offset by 8(plus or minus). For example if a male gyarados parent has a special value of 10, the female child's special value can be either 10 or 2. The important thing to understand with this rule is that the female child with the spcecial value being either 10 or 2 will also always pass down either 10 or 2 to its opposite gendered child.

3: The shiny DVs

For a pokemon to be shiny, it needs 10 DVs in defense, special and speed. And needs 2,3,6,7,10,11,14 or 15 in attack. As the gender of the pokemon is also determined by the attack DVs, female pokemon with a 7/8 chance of being male (e.g.starters) can never be shiny as their attack DVs will always be 0 or 1.

4: Passing down the shiny genes

To start trying to breed for a shiny pokemon, you first need what I call the shiny genes; a pokemon with 10 defense DVs and 10 or 2 Special DVs as these are the DVs that will be passed on. Luckily in Gen 2 we get to catch a shiny Gyarados so it is very simple to obtain the shiny genes. From here every opposite gendered pokemon that has the shiny Gyarados as a parent will have the shiny genes, whether they are shiny themselves or not.

For Example: If I wanted to get a shiny Eevee, I can use an Ekans to pass on the genes from Gyarados to Eevee. I made a quick diagram in paint to show the process.

The Eevee has a 1/64 chance of being shiny because only male Eevees can be shiny. If trying to breed a pokemon with a 50/50 gender ratio, the shiny chance will be 1/128.

5: Shiny breeding ditto

A lot of guides insist using a glitch in RBY to get a shiny ditto using the shiny gyarados and the move mimic. But if you are looking for a more legitimate way of getting a ditto for shiny breeding and patient enough, at 1/128 odds it's possible to find dittos in cerulean cave in RBY with high enough levels to check the DVs immediately and its also possible to repel trick so that only dittos appear on the floor with Mewtwo.

Conclusion

I hope this guide helps anyone trying for shinies in the VC games and hope this guide wasn't too confusing since English is my second language.