90° angle in the horizontal plane, located more than 200 m underground. The excavation phase of tunnels was started in May 2012 and was completed on 31 March 2014. The construction of KAGRA was completed 4 October 2019, with the construction taking nine years. However, further technical adjustments were needed before it could start observations. The "baseline" planned cryogenic operation ("bKAGRA") was planned to follow in 2020. Operational history After the initial adjustment operations, the first observation run started on 25 February 2020. Because of COVID-19, the observation run was ended 21 April 2020. The sensitivity during this run was only 660 kpc (binary neutron star inspiral range). This is less than 1% the sensitivity of LIGO during the same run, and around 10% of KAGRA's expected sensitivity for the run. Upgrades to improve the sensitivity are ongoing between runs. The first detections were made in collaboration with LIGO and Virgo and were reported 11 November 2021. See also TAMA300, an early prototype in Japan. CLIO, a current prototype that is developing cryogenic technologies. DECIGO, a proposed Japanese space-based interferometer. References External Official page (English) KAGRA experiment record on INSPIRE-HEP Interferometric gravitational-wave instruments Astronomical observatories in Japan University of Tokyo