About YAOKU
YAOKU is a free browser-based number and logic puzzle operated by Elijah Maxwell. It combines crossing sums, neighboring product clues, and a finite set of Loose Cards. It is for players ages 13 and older and does not require a player account.
Generated puzzles, not a fixed collection
Random creates a fresh Easy, Medium, or Hard board in your browser. The Daily is generated and verified on the server and saved as the same challenge for everyone for one America/Chicago calendar day. There is no fixed Library or numbered puzzle collection to browse.
The challenge is to reconcile several kinds of evidence: each sum group has a total and cannot repeat a digit; a product badge constrains its two neighbors; and each Loose Card copy must be used exactly once. Fixed givens stay in place and do not consume cards. The rules and worked examples explain how these clues connect.
What stays on your device
Your player name, entries, notes, preferences, personal statistics, and visit streak are stored locally in this browser. They are not an online profile and do not automatically sync across devices. Clearing browser storage can remove these records. The visit streak reflects visits rather than consecutive puzzle completions.
What sharing makes public
A six-digit puzzle link shares the exact starting board, not your entries or notes. A shared completion result can show time, hints, and an optional visit streak, but not your local name or solution. Anyone with a shared link can open its shared content. Public leaderboards and Daily Rivals are not available.
Privacy and contact
YAOKU uses website analytics and reporting as described in the Privacy Policy. Local-only player records do not mean that the site has no server requests or analytics. See the Terms of Service and contact page for the current policies and email addresses.