# Notation and Transposition

For the purpose of transposition, Bard supports these four notation systems:

- [English](https://en.wikipedia.org/wiki/Musical_note#12-tone_chromatic_scale)
- [German](https://en.wikipedia.org/wiki/Musical_note#12-tone_chromatic_scale)
- [Nashville](https://en.wikipedia.org/wiki/Nashville_Number_System)
- Roman (the same as Nashville except using Roman numerals)

The English notation is the default.
If you live in, for example, central Europe or Scandinavia, you may want to set `notation = "german"` in your `bard.toml`.

However, if you don't use transposition features, you don't need to worry about this; Bard will simply use
whatever you enter as chords. Correct notation setting is only needed when using transposition so that Bard can
understand the chords you are using.

### Transposition

To transpose your chords, use the `!±X` syntax, where X is the number of halftones.
The chords will be transposed from that point onward. For example:

```Markdown
# Danny Boy

!+5

1. `G7`Oh Danny `C`Boy, the pipes, the ``C7``pipes are `F`calling
```

will shift the chords up by 5 halftones, aka _perfect fourth_:

![transposition example 1](./assets/transpose-1.png)

If needed, use `!+0` to go back to the original scale.

### Second Set of Chords

Bard can also generate a second line of chords as a transposition of the first one.
Use the `!!±X` syntax to generate a second row. The second row is, by default,
rendered in blue font. For example:


```Markdown
# Danny Boy

!!+5

1. `G7`Oh Danny `C`Boy, the pipes, the ``C7``pipes are `F`calling
```

renders as:

![transposition example 2](./assets/transpose-2.png)

### Notation Conversion

Besides transposition, the notation system of chords can also be converted using the `!notation` syntax,
where `notation` is one of the names listed above in lowercase.

This can be used just like transposition (and together with it) as well as for the second line of chords.

A comprehensive example of transposition and notation conversion to generate a 'scale agnostic' second line:

```Markdown
# Wild Mountain Thyme

!!-7
!!roman

1. O the `G`summer `C`time `G`has come
And the `C`trees are sweetly `G`bloomin'
And the `C`wild `G`mountain `Em`thyme
```

![transposition example 3](./assets/transpose-3.png)