A logic grid puzzle gives you a few people, a few kinds of thing and some clues, and asks who goes with what. On Yukti, a daily logic puzzle at playyukti.com, it comes as a plain grid or as the spirit's riddle, a tale ending in a question. Below: where it comes from, the method and a small example.
Kind of thinking: Deduction
What is a logic grid puzzle?
Each person has one thing from each category, and no two people share one. The grid has a row for each person and a column for each thing. Ruling a pair out crosses a cell; confirming a pair ticks it. Each clue removes some possibilities, and together they leave only one answer.
On Yukti, crossing a cell out is a free note. Only confirming a pair counts as a step, and a confirm is accepted only when the clues make it certain.
Where does it come from?
The best-known ancestor is the Zebra Puzzle, published in Life International on 17 December 1962: five houses, fifteen statements, and two questions, "Who drinks water? Who owns the zebra?". The answer, with the names of readers who solved it, ran on 25 March 1963. It is often called Einstein's Riddle or credited to Lewis Carroll, but there is no evidence for either.
Yukti's riddle days come from a much older book: the Vetala Panchavimshati, "Twenty-five tales of the vetala". A king carries a vetala, a spirit, through the night, and each time it tells a tale that ends in a riddle for the king to answer. One of its oldest tellings is in Somadeva's Katha Sarit Sagara, from the 11th century.
How do you solve one?
Five habits do most of the work:
- Start with the direct clues. "Bina has the parrot" confirms a pair straight away.
- One tick, many crosses. A confirmed pair rules out everything else in its row and its column: nobody else has the parrot, and Bina has nothing else from that category.
- Look for the last one standing. When every cell but one in a row is crossed, the one left is the answer.
- Chain across categories. If the dog's owner drinks tea, and Chetan has the dog, Chetan drinks tea.
- Read "either" and "neither" carefully. "The cat is Asha's or Bina's" rules the cat out for everyone else. "Neither Asha nor Bina has the dog" crosses two cells.
A worked example: three people, two categories
Asha, Bina and Chetan each have one pet (a cat, a dog, a parrot) and one drink (tea, coffee, milk). The clues: 1. Bina has the parrot. 2. Asha doesn't have the dog. 3. The person with the dog drinks tea. 4. Asha doesn't drink milk.
- Clue 1: confirm Bina and the parrot.
- Clue 2: Asha has neither the dog nor the parrot, so Asha has the cat.
- That leaves the dog for Chetan.
- Clue 3: the dog's owner drinks tea, so Chetan drinks tea.
- Clue 4: Asha doesn't drink milk, and tea is Chetan's, so Asha drinks coffee.
- Bina drinks milk, the only drink left.
Six pairs, six steps, and every one certain. Clues 2 and 4 never name an answer; they only cross cells, and the last one standing does the rest.
Riddle days: the spirit's question
On riddle days the grid comes inside a tale. The spirit tells of three to five travellers who came to a forest inn, each carrying one thing, and the clues are what it lets slip. The tale ends with a question, such as "Who carried the lamp?". You confirm every pair as usual; the pair that answers the question is announced as you confirm it, and the Solved screen gives your answer to the spirit.
How does Yukti help when you are stuck?
A confirm that doesn't fit is stopped, and the board says which clue it breaks. It still counts as a step. A nudge asks you a question, such as "Which clue tells you the most about Asha's pet?". The day after, yesterday's route confirms the pairs in order, with the clue behind each.
Sources
Read on 26 October 2026: Zebra Puzzle (Wikipedia); Vetala Panchavimshati (Wikipedia); The Katha Sarit Sagara, Book XII (C. H. Tawney's translation, Project Gutenberg).