The Death Blossom Sudoku Technique Explained

Identify the stem cell

The pattern begins with one unsolved stem cell containing several candidates, often three. Imagine that the stem contains heart, circle, and lotus. One of those shapes must be true, but you do not need to know which one. Instead, each stem candidate will connect to a different Almost Locked Set, often called a petal. An Almost Locked Set has one more candidate than cells, such as two cells containing three candidates in total. If one particular candidate is removed from that set, the remaining candidates become locked into its cells. Death Blossom logic uses the stem to guarantee that one petal will become locked. Full and accurate Notes are essential, so this technique belongs near the end of a Hard or Extreme solve rather than at the beginning.

Build one petal for each stem candidate

Find an Almost Locked Set linked to the heart candidate in the stem. Every heart candidate inside that petal must see the stem, so a heart placed in the stem would remove heart from the petal and lock its remaining candidates. Repeat the construction for circle and lotus using separate petals. Each petal should also contain one common target candidate, such as crescent. The petals do not need to share cells, and they can lie in different units. What matters is the connection: if a particular stem candidate is true, its matching petal loses that candidate and becomes a locked set. Since crescent remains among the petal's candidates, that locked petal must contain crescent somewhere within its own cells. Carefully count each petal. Two cells must contain exactly three combined candidates, three cells must contain exactly four, and so on.

Eliminate the shared target

Now consider every possible value of the stem. If the stem is heart, the heart petal locks and contains crescent. If the stem is circle, the circle petal locks and contains crescent. If the stem is lotus, the lotus petal locks and contains crescent. One of these cases must occur, so crescent must appear in at least one petal. Any outside crescent candidate that sees every possible crescent position across all petals can therefore be removed. This visibility requirement is strict. Seeing one cell in each petal is not enough if another crescent position in that petal remains unseen. Because the pattern combines several sets, verify it backward after finding a target. Check the target's visibility, each petal's candidate count, and every link to the stem. Then make the single elimination and rescan the grid before searching for another large pattern.

• The stem is one cell with several candidates.
• Each stem candidate connects to its own Almost Locked Set.
• All matching candidates in a petal must see the stem.
• Every petal contains the same target candidate.
• The target cell must see every target occurrence in every petal.
• One incorrect note can invalidate the entire pattern, so verify slowly.