Stuck? Tap the hint button 💡 at the end of the action bar below the digit buttons. A card takes the keypad's place and shows the next step: which technique it uses, where, and why it works. The cells and candidates involved are marked on the grid.
The button at the bottom of the card makes the move for you, placing the digit or erasing the candidates. Or close the card with × and make the move yourself.
When a step takes more explaining, such as a chain, the card offers Show me, which walks through the reasoning one move at a time on the board. Pause it, or step back and forward with the arrows.
With the digit assistant off, a hint goes straight to a digit you can place. With it on, a hint may instead erase candidates, one step of reasoning at a time.
If a digit you placed is wrong, or you erased the candidate a cell needs, the hint says so first and offers to put it right.
Seeing a hint card is a peek. From the moment one appears, this game can no longer win the applause and the full flash: it gets a single flash and a ta-da instead. A red ring on the hint button marks the peek. Closing the card without using it does not take the peek back, and neither does starting over.
There is always a next step. The hardest are forcing nets, which the card names Cell Forcing Net. When nothing a person would use applies, the card says Brute Force, and the step it gives is still correct.
In Settings, turning off Enable hints takes the hint button away. Hint arrows draws arrows between the linked cells of a hint. A blue arrow is a strong link: one of its two ends must hold the digit. A red arrow is a weak link: its two ends cannot both hold the digit. Red arrows also point at the candidates the step erases. In a forcing net the arrows along the trail are all blue, and mean something else: each says that one candidate forces the next. With the arrows on, the steps of Show me name them by color.