The chances of getting a replacement are poor, with Tokyo’s relations with Beijing at their lowest point in years amid tensions over Taiwan.

Japanese panda fans gathered Sunday for the final public viewing at Tokyo’s Ueno zoo before twins Xiao Xiao and Lei Lei return to China this week.

Their departure on Tuesday will leave Japan with no pandas for the first time in half a century, and the chances of getting a replacement are poor, with Tokyo’s relations with Beijing at their lowest point in years.

China first sent pandas to Japan in 1972, a gift meant to mark the normalization of diplomatic ties between the two wary neighbors. The cuddly black-and-white bears immediately won Japanese hearts, and a dozen successors have become national celebrities.