noun
lifting stone; strength stone
A heavy stone used historically in Japan for tests of strength, often in festivals or competitions.
村の祭りで力石を持ち上げる競技が行われた。
At the village festival, a competition to lift the strength stone was held.
Compound of 力 (chikara, 'strength') and 石 (ishi, 'stone'). The reading chikaraishi is a straightforward combination.