Chai & Coffee is played on a square grid where every cell can hold chai, coffee, or stay empty until you choose. Tap once for chai, twice for coffee, and a third time to clear the cup. Pre-filled cups are fixed clues and cannot be changed.
The puzzle is solved when every cell is filled and three rules hold at once. First, each row and each column must contain the same number of chai cups and coffee cups. On an eight-by-eight board that means four of each drink per line; smaller boards scale accordingly. Second, you may never place three identical drinks next to each other horizontally or vertically. Third, small badges between neighbouring cells show whether those cups must match (=) or differ (×).
Worked example
Imagine a four-by-four line that must hold two chai and two coffee with no triples. If the leftmost cup is a given chai and the badge to its right is ×, the neighbour must be coffee. If the next badge is =, that third cup is coffee as well, which already forces the fourth cup to be chai so the counts balance. When a = sign sits between two cells in a row, treat them as a linked pair while you scan the rest of the line for count parity.
Strategy tips
Scan for forced triples early. Whenever two adjacent cups already match, the cell on either open side cannot take the same drink, or you would create three in a row. Mark those eliminations before guessing.
Use equality chains. A string of = signs ties cups into blocks that must share one drink. Once one member of the block is known, the whole block follows, which often settles an entire row or column.
Balance counts last. After parity and triple rules narrow choices, count how many chai and coffee remain for each line. If only one slot is open and one drink is missing, that slot is decided without trial and error.
Undo is always available if you want to back up a step. Levels increase grid size and clue density, but the same three rules govern every board.