Skyscraper and Two-String Kite: Two Single-Digit Chains

Single-digit chains are easier to learn when you focus on strong links: a unit where a candidate has exactly two possible positions.

A Skyscraper and a Two-String Kite connect two such links and eliminate the candidate from cells that see both endpoints.

Map strong links

Choose one digit and find two rows or columns where it appears exactly twice. Mark each pair as a strong link. The pattern depends on those pairs being complete, not merely small.

Build a Skyscraper

Use two parallel strong links with one endpoint aligned or connected. The two free endpoints become the chain’s roof; any cell seeing both cannot contain the digit.

Build a Two-String Kite

Join a row strong link and a column strong link through a box strong link. The two outer endpoints again force an elimination in their common peer.

Check visibility, not symmetry

The drawing may not look like a neat skyscraper or kite. Confirm that the endpoint cell really sees both relevant ends and that every link is strong.

Return to the grid

After one elimination, stop mapping chains and inspect the changed units. A single-digit chain is valuable because it creates ordinary progress, not because it is visually impressive.