According to Official Guinness Records,
Tatsuo Kitano (Japan) has a collection of 7,845 kappa related items as of 2 June 2009, which he has amassed since the 1960's. Kappa is a type of river sprite found in Japanese folklore.
His collection is housed in a specially built building next to his house, which is open to the public. Kappa is well known as Sandy in the Japanese TV series Monkey.
For a complete list of 2009 records, please visit 2009 Guinness Records in Japan.