OSAKA (Kyodo) Foreign tourists watch in amusement as some 20 people dressed in bright red samurai armor pick up cigarette butts and other rubbish around Osaka Castle with tongs designed to look like swords.

They are members of the nonprofit organization Osaka Kacchutai (Osaka Armor Corps), which has been cleaning up the castle's perimeter once a month since 2003.

The volunteers were soon surrounded by tourists, who pestered them to pose for photos.

"I made this," said Hachiro Ikegami, 73, getting more oohs and aahs as he showed off his armor and explained the castle's history in English.

The armor is handmade from cardboard and cardboard boxes colored with special paint that reinforces its strength.

"Armor made of cardboard was used in battles because it was very light," said Kazumi Kawai, a part-time high school teacher who heads the NPO. "They were treasured by feudal lords of the Warring States Period (15th and 16th centuries)."

The group emerged after Kawai, 47, began teaching a class on handmade samurai armor. When the members first started cleaning the castle's perimeter, they accumulated about a truckload of garbage. These days they only find enough to fill about two big garbage bags.