Japanese footballers need to develop thicker skins to deal with the racism of the European leagues, national team goalkeeper Eiji Kawashima said.
The Standard Liege gloveman was speaking after it emerged striker Yuki Nakamura had left his Slovakian club Rimavska Sobota because of racist abuse.
"It is a pity that something happened like that, but, and this is just my opinion, Japanese players... have to be really tough in a foreign country. It is not easy," Kawashima told Kyodo News after Japan's 3-0 drubbing of Latvia on Wednesday.
In 2011, Kawashima was reduced to tears midway through a game in Belgium after opposition fans started taunting him with repeated chants of "Fukishima, Fukishima", referring to the 2011 nuclear disaster.
"Sometimes people are against us just because we are Asian. Some stupid people think that way and just joke in that way and we just need to be tough," he said.
"Living in Japan is really comfortable and really easy but you know when you go abroad the situation isn't always the same."
Kawashima's comments come after Nakamura wrote on his blog about the intolerable racism he had suffered in Slovakia.
"Unfortunately, I have come home because I was subjected to racism at the club I belonged to, Rimavska Sobota, and could not live there any more," the footballer wrote, adding he had received no backing from teammates.
Kawashima said he was sympathetic, but believed players had to face up to the challenge.
"Maybe the situation for him was really tough and he was really alone. But we have got to be tough and if there is something wrong you have to stand against it."
Kawashima kept a clean sheet in his side's victory over Latvia in a World Cup warm up, which saw Stuttgart striker Shinji Okazaki bag a brace.
Japan are one win away from reaching the finals in Brazil and will next take on Jordan on March 26.