THE Japanese have produced more than their fair share of single-minded masters. There are sushi masters who have devoted their lives to the immaculate slicing of raw fish and there are green tea masters who have spent decades honing the art of brewing the perfect cuppa.

And then there is Tetsuya Nishio, the undisputed grand “puzzle master” of Su Doku: a bespectacled fiend from the darkest suburbs of Tokyo who spends his every waking hour devising abominable new ways to torture our brain cells. His only weapon is logic, but, in his own words, “it is a knife that kills”.

His commitment to deviousness is absolute, and he is notorious among the millions of Su Doku fans spread across Japan. When Su Doku champions burst into tears of frustration over the latest “super difficult” puzzle, his is the name they curse out loud. Master Nishio has trained almost all of Japan’s greatest champions and apprentice puzzle masters.

And now, in its first sighting outside Japan, one of the cruellest twists on the basic Su Doku game has reached The Times straight from Nishio’s diabolical stable.

“Of course I have recently read in the Japanese press about the extraordinary Su Doku boom in the UK and I was very happy to see it happening,” says the puzzle master, “but Britain has not had the puzzles for long enough to become fully used to their complexities. This new variation will be a dreadful challenge for you.”

Samunamupure (it translates as “sum number place” and we have named it Killer Su Doku) is a variation that has been evolving among Nishio and his small clan of devoted puzzle students for some years. It is, he says, the perfect example of a next-generation puzzle: it is simple to understand, requires no insider knowledge or training and rewards pure and simple logic.

The digits within the oddly shaped “inner boxes” (marked by dotted lines) must add up to the small number written in the top corner of that box. Apart from that, all the normal Su Doku rules apply. “The really satisfying part,” says Nishio with an evil smirk, “is that you can design a Samunamupure puzzle in a way that you do not need to insert any starting numbers in the grid. I think that will make some people very disturbed.”

The original samunamupure was devised a few years ago by Miyuki Nisawa, one of the puzzle-master’s most accomplished pupils. Under his tutelage she has further sharpened the puzzle’s bite, gradually stretching its difficulty while retaining the appallingly addictive qualities of the Su Doku genre. Others have joined her in honing the puzzles.

Yumiko Meguro, another of the clan, said: “Britain will be surprised and confused by Samunamupure at first, but once you have realised its secret, you will be absolutely lost to it.”