Tokyo stocks rose marginally on Thursday morning in circumspect trading ahead of former U.S. Federal Bureau of Investigation Director James Comey's testimony in Congress, Britain's general election and the European Central Bank's policy meeting.

The 225-issue Nikkei Stock Average edged up 9.35 points, or 0.05 percent, from Wednesday to 19,993.97.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, inched 1.12 points, or 0.07 percent higher, at 1,598.21.

Air transportation and insurance-linked stocks comprised issues that gained the most by the morning break.