Stable income: Somewhat stable

I’d rate it a 3 out of 5 because while there is a decent baseline of demand for chess coaching, especially with the rise of online platforms, it can be unreliable at times due to fluctuations in client interest and competition. It's not a 2 because there is a consistent interest in learning chess, but it's not a 4 because the income can vary significantly based on client retention and market saturation.