Multi-coloring: compare separate color chains
Multi-coloring extends simple coloring by keeping separate two-color components for the same digit until they interact.
Key idea
When a color in one component sees a color in another, their opposites become linked; a candidate that sees the resulting true alternatives can be removed.
See the move, step by step
Compare two short components for candidate 7 in box 1.
Step 1 of 4
Build separate components
Follow candidate 7 through conjugate pairs, without pretending disconnected pairs belong to one chain.
Step 2 of 4
Assign colors within each component
Each strong pair receives opposite colors. The weak interaction between R1C2 and R2C2 connects the implications.
Step 3 of 4
Use the interaction
R3C1 sees the alternatives established by the interacting components, so its 7 cannot survive.
Step 4 of 4
Keep component identities intact
Remove 7 from R3C1, but keep the remaining colors separate until another link proves more.
Try it on today's puzzle
Use distinct color pairs for disconnected components. Only combine their implications when you can point to a real peer relationship between them.
Play today