Come Giocare a XV Sudoku
X tra le celle significa che sommate danno 10; V significa che sommate danno 5
Le regole
Si applicano le regole standard del Sudoku: riempi ogni riga, colonna e box 3×3 con le cifre 1–9, ciascuna apparendo esattamente una volta.
XV Sudoku (chiamato anche Ten-Five Sudoku) posiziona marcatori X e V tra celle adiacenti. Una X significa che le due celle sommate danno 10; una V significa che sommate danno 5. Molti puzzle XV usano il vincolo negativo: l'assenza di un marcatore garantisce che la coppia non sommi né a 10 né a 5. Combinato con il Sudoku standard, questo fornisce vincoli molto stretti su tutta la griglia.
Per sapere da dove viene questo puzzle, come si confronta con varianti correlate e un riepilogo della strategia, consulta il nostro XV Sudoku panoramica varianti.
A Colpo d'Occhio
Come Risolvere XV Sudoku
Domande Comuni
Cos'è l'XV Sudoku? ▾
XV Sudoku is a variant where X and V symbols appear between adjacent cells. An X marks two cells that sum to 10. A V marks two cells that sum to 5. Standard Sudoku rules apply, and — critically — all X and V relationships are fully marked: if there is no symbol between two adjacent cells, those cells are guaranteed not to sum to either 10 or 5.
What pairs sum to 10 (X)? ▾
The valid X pairs are: 1&9, 2&8, 3&7, 4&6. Note that 5&5 sums to 10 but standard Sudoku uniqueness rules prevent two 5s from being adjacent in most cases. The X constraint immediately limits each marked cell to a small set of candidates.
What pairs sum to 5 (V)? ▾
The valid V pairs are: 1&4, 2&3. Only four digits can ever appear in a V cell: 1, 2, 3, or 4. This makes V markers particularly powerful for restricting candidates in the lower half of the digit range.
How does the no-symbol constraint work? ▾
All X and V relationships are shown — if two adjacent cells have no symbol, their sum is guaranteed to be neither 5 nor 10. This negative constraint eliminates candidate pairs from unmarked cell boundaries and is often as useful as the explicit symbols.
Is XV Sudoku hard to learn? ▾
The rules are simple to memorise. The challenge is applying both the positive (X, V) and negative (no symbol) constraints simultaneously across the entire grid. Easy puzzles are very accessible; expert puzzles require exhaustive tracking of all adjacent-cell relationships.
How long does XV Sudoku take to solve? ▾
Easy puzzles take 8–15 minutes. Medium puzzles run 15–30 minutes. Hard puzzles average 30–60 minutes and expert puzzles often exceed 90 minutes. The no-symbol negative constraint is the most time-consuming to apply systematically across a densely marked grid.