The 3rd World Sudoku Championship (with classic and variant puzzles) has been won by Thomas Snyder of the United States. In second place is Yuhei Kusui of Japan and Jakub Ondrousek of the Czech Republic who placed third. Mr. Snyder also won the Classic Sudoku Championship (no variants), followed by David McNeill of the United Kingdom in second place and Michael Ley of Germany in third place. Team competition results show the Czech Republic in first place, followed by Japan and Germany in 2nd and 3rd place, respectively.
One of the variants shown in the Instruction booklet (First Link in the Downloads Section, a PDF file) for this year’s contenders is known as Sudoku XV. The fewer numerical clues are offset by number pair relationships as sums of 5 or sums of 10. You may use the full force of sudoku analysis to fill in numbers and get the bonus of a neighboring pair value.
There seems to be few puzzle sources for this variant except in Competition instruction booklets. I hope this is temporary. It’s an interesting blend between a limited Kakuro and Sudoku.