  One of the ultimate goals of the study of iron-based superconductors is to
identify the common feature that produces the high critical temperature (Tc).
In the early days, based on a weak-coupling viewpoint, the nesting between
hole- and electron-like Fermi surfaces (FSs) leading to the so-called $s\pm$
state was considered to be one such key feature. However, this theory has faced
a serious challenge ever since the discovery of alkali-metal-doped FeSe (AFS)
superconductors, in which only electron-like FSs with a nodeless
superconducting gap are observed. Several theories have been proposed, but a
consistent understanding is yet to be achieved. Here we show experimentally
that a hole-like band exists in KxFe2-ySe2, which presumably forms a hole-like
Fermi surface. The present study suggests that AFS can be categorized in the
same group as iron arsenides with both hole- and electron-like FSs present.
This result provides a foundation for a comprehensive understanding of the
superconductivity in iron-based superconductors.
