TOKYO, Jan. 11, 2011  -- A mysterious donor claiming to be a popular Japanese cartoon hero has set off a national wave of gift-giving to underprivileged children in Japan.

Dozens of orphanages and child welfare centers across the country have reported receiving backpacks in the past few weeks, even cash from somebody claiming to be Naoto Date, the main character of 1960s comic "Tiger Mask."

Date is an orphan who becomes a professional wrestler known as Tiger Mask. He donates money to his orphanage after he becomes successful.

The real-life spate of gift-giving began Christmas Day when 10 boxes full of backpacks were left behind at a child counseling center in the Gunma Prefecture, an hour outside Tokyo. Employees found the boxes at the entrance, with a note signed by "Naoto Date."

The leather bags traditionally worn by elementary school students here sell for more than $300 each.

More than 90 similar acts of generosity have been reported since. A large retail chain in the northern Iwate Prefecture said it received about $1,200 in an envelope with a letter reading, "There are Tiger Masks all over Japan. Please use this for our most promising children."

Masatoshi Kikuchi received a box full of pencils and pencil sharpeners for children at his welfare facility in Yokohama. The attached letter read, "I was inspired to do this by Tiger Mask."

"This really helps me out because I really need the supplies," Kikuchi told broadcaster NHK. "I imagine this person to have a big heart."

The anonymous superheroes have even gone to the police to drop off the expensive bags. Twenty-one different facilities reported receiving boxes Tuesday alone.

The gifts haven't been limited to school supplies. A welfare facility in the Yamagata prefecture reported receiving five bags of rice, 44 bushels of greens onions and 11 Chinese cabbages. Thet shipment came with roughly $120 in cash and a letter signed "Naoto Date of the countryside."

Copycat Superheroes

All the attention given to "Tiger Mask" seems to have inspired other Japanese superheroes as well. A facility in southwest Japan reported receiving gifts from folk-hero Momotaro, translated as "Peach Boy." Boxes of rice dumplings, a special treat prominently featured in the folk story, were left behind.

Despite the nationwide search for the man behind the original Christmas day gifts, nobody claiming to be "Naoto Date" has come forward.