The trust, which currently has almost 37% of its assets in Japan, hiked net asset value by 15.5% and NAV total return by 17.6% in the first half of 2013.
The tightly-focused trust, with 30 to 40 stocks, does not use a benchmark but notes returns of 8.5% from the FT all-share index and 13.9% in the FT all-world index over the period.
Chairman Teddy Tulloch says it was "a particularly encouraging performance as our investments in Japan began to bear fruit".
The trust had first raised its holdings in Japan to over 20% of the trust in 2010, a few months before the earthquake and tsunami struck in March 2011.
Despite the dramatic recovery in Japanese share prices from November 2012, the trust had increased its exposure further to 36.9% by the end of June, funded by a cut in Asia from 20.5% to 14.1% and a halving of UK exposure to 6.2%. The discount was 5.2% and the trust continued to buy back shares.
Mr Tulloch added: "The patience of our investment manager and the conviction that Japanese equities represented outstanding value are now being rewarded."
l Mid Wynd International, the £68m trust run by Baillie Gifford in Edinburgh had a "disappointing" year to June 30, chairman Richard Burns has said. NAV was up 10.1% and the share price by 11.2% but the FT World Index was up 18.9%.