• # Technical Documentation:Other

• ### Other

Introduction
Generation 2 saw the introduction of Headbutt as a field move, as a new way to obtain different Pokemon.
By now, players probably know that certain rare Pokemon can only be found in certain headbuttable trees, but may be unaware how to differentiate moderate encounter trees from low encounter trees.
The intention behind this document, is to log the necessary information relating to this.

Mechanic Explanation
On every map, every tile can be assigned a value that ranges from 0 to 9, based on it's distance from tile 0 (the upper left tile).
When a tree falls on said tile, the value on the tile will be used in the determination of whether the headbuttable tree will result in a moderate or low encounter type.

The formula used to determine the tree's index:

`index = ( ( X * Y + X + Y ) / 5 ) % 10`

The determination whether the index will result in moderate or low encounter type, depends on the value of the Trainer ID.
The formula used to determine the rare index (basically the last digit/right-most digit on the TID):

`rare_index = trainer_id % 10`

Example of usage
For example, if your Trainer ID is 26117, the rare index is 7.
Meaning every tree with the index 7 on that map will result in a low encounter type of tree.
Here's an example:

With the circled tree in the image, users can potentially encounter Heracross there!

Implemention
As seen in the image above, there's actually a web tool that presently works.
The web tool is created by u/TShadowKnight on reddit.

In the event the tool goes offline, I've got all the maps data recorded! (Or if you prefer to know which map has the mon, but want to go hunting.)
The table below shows which index tree is available on which map.

Map Available Tree Indexes Missing Tree Index Unique to Rare Tree on Map
Gold Silver Crystal
Azalea Town 0, 1, 2, 3, 4, 5, 6, 8, 9 7 Pineco Pineco Pineco
Ilex Forest 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Pineco Pineco Butterfree, Beedrill,
Noctowl, Pineco
Lake of Rage 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Pineco Pineco Pineco
Route 26 9 0, 1, 2, 3, 4, 5, 6, 7, 8 Pineco Pineco Pineco
Route 27 0, 1, 3, 4, 5, 7, 9 2, 6, 8 Pineco Pineco Pineco
Route 29 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Heracross Heracross Pineco
Route 30 0, 1, 2, 3, 4, 5, 6, 7 8, 9 Heracross Heracross Pineco
Route 31 1, 2, 3, 4, 5, 6, 7, 8, 9 0 Heracross Heracross Pineco
Route 32 1, 2, 3, 5, 6, 7, 8, 9 0, 4 Heracross Heracross Pineco
Route 33 6, 9 0, 1, 2, 3, 4, 5, 7, 8 Heracross Heracross Heracross
Route 34 0 1, 2, 3, 4, 5, 6, 7, 8, 9 Pineco Pineco Pineco
Route 35 0, 5, 6, 9 1, 2, 3, 4, 7, 8 Pineco Pineco Pineco
Route 36 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Pineco Pineco Pineco
Route 37 0, 3, 4, 5, 7, 9 1, 2, 6, 8 Pineco Pineco Pineco
Route 38 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Pineco Pineco Pineco
Route 39 2, 7, 8 0, 1, 3, 4, 5, 6, 9 Pineco Pineco Pineco
Route 42 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Heracross Heracross Heracross
Route 43 0, 1, 2, 3, 4, 5, 6, 7, 8, 9   Heracross Heracross Pineco
Route 44 0, 1, 2, 3, 4, 5, 6, 7, 9 8 Heracross Heracross Heracross

For images of the specific maps, go here:

Sources