  In this multi-messenger astronomy era, all the observational probes are
improving their sensitivities and overall performance. The Focusing on
Relativistic universe and Cosmic Evolution (FORCE) mission, the product of a
JAXA/NASA collaboration, will reach a 10 times higher sensitivity in the hard
X-ray band ($E >$ 10~keV) in comparison with any previous hard X-ray missions,
and provide simultaneous soft X-ray coverage. FORCE aims to be launched in the
early 2030s, providing a perfect hard X-ray complement to the ESA flagship
mission Athena. FORCE will be the most powerful X-ray probe for discovering
obscured/hidden black holes and studying high energy particle acceleration in
our Universe and will address how relativistic processes in the universe are
realized and how these affect cosmic evolution. FORCE, which will operate over
1--79 keV, is equipped with two identical pairs of supermirrors and wideband
X-ray imagers. The mirror and imager are connected by a high mechanical
stiffness extensible optical bench with alignment monitor systems with a focal
length of 12~m. A light-weight silicon mirror with multi-layer coating realizes
a high angular resolution of $<15''$ in half-power diameter in the broad
bandpass. The imager is a hybrid of a brand-new SOI-CMOS silicon-pixel detector
and a CdTe detector responsible for the softer and harder energy bands,
respectively. FORCE will play an essential role in the multi-messenger
astronomy in the 2030s with its broadband X-ray sensitivity.

High Energy Astrophysical Phenomena;Instrumentation and Methods for Astrophysics