This game-worn, autographed jersey of Tetsuya Yamaguchi from the Samurai JAPAN team is a notable piece for collectors, particularly given its association with the Yomiuri Giants and the historical context of the 2009 World Baseball Classic championship.

Game-worn items from prominent athletes in Japan often command high interest due to their rarity and the personal connection they embody, making this jersey a unique highlight in a collector's portfolio.

The condition is crucial; this item's authenticity and the presence of Yamaguchi's signature enhance its value, while its provenance ensures that it reflects the standards of quality typically associated with Japan-sourced memorabilia.

At ¥300,000, this autographed jersey aligns with current market trends for premium collectibles in Japan, which continue to appreciate in value as the nostalgia for significant sporting moments grows.