The Nagano District Court has found a former judo coach guilty of inflicting a serious brain injury upon a student after a lay panel overturned an initial decision by prosecutors not to indict him.

Takeshige Kojima, who faced a suspended one-year prison term, threw then-sixth-grader Musashi Sawada at a training hall in Matsumoto, Nagano Prefecture, in May 2008, leaving him with impaired consciousness caused by acute subdural hematoma, the indictment handed down Wednesday said.

In the ruling, Presiding Judge Akira Ito said Kojima was at fault for "not considering the student's skill level and build, and failed to apply the appropriate force."

"The defendant was obliged to pay close attention in giving the judo lesson, but he mistakenly threw and injured (Sawada)," Ito said. "It was serious negligence."

Local prosecutors declined to indict Kojima as they did not have evidence proving he could have foreseen the accident. But the special Committee for the Inquest of Prosecution twice decided he should be indicted, prompting lawyers appointed to act as prosecutors to mandatorily indict him in May 2013.

The rarely used inquest system has been criticized as a form of double jeopardy.