The brush aisle can make watercolor feel much more complicated than it is. Round, flat, angled, mop, liner—why are there so many shapes, and do you really need all of them?
No. A good round brush can carry you through most beginner exercises. The other shapes simply make particular marks easier. Think of this list as a map, not a shopping requirement.
1. A medium round brush
This is the workhorse. A round brush with a fine point can make a broad stroke, a narrow line, petals, leaves, and controlled washes. If you buy only one brush at first, choose a medium round that springs back into shape and holds enough water for the size of paper you use.
2. A small round brush
A smaller round helps with tiny shapes and finishing details. It should complement your medium brush, not replace it. Try not to do an entire painting with a miniature brush; that often creates scratchy marks and makes washes harder than they need to be.
3. A flat brush
Flat brushes are useful for straight edges, geometric marks, broad bands of color, and wetting an area evenly. Turn the brush on its edge and it can also create a surprisingly thin line.
4. A mop or wash brush
A soft mop holds lots of water and is lovely for skies, loose backgrounds, and generous wet-on-wet passages. It is most helpful when you work larger. For a small sketchbook, your medium round may already hold enough water.
5. A liner or rigger
This long, narrow brush is made for flowing lines: stems, branches, whiskers, grasses, and expressive outlines. It is a useful specialty brush once you are comfortable controlling the water in your basic round.
What matters more than the label
Look for a brush that forms a reliable point or edge, releases water evenly, and feels comfortable in your hand. Synthetic brushes are a practical place to begin, and you do not need a huge matching set. Add a new shape only when you can name the mark your current brushes cannot make easily.
For more detail about the actual brushes I use, visit my watercolor brush guide.