  We present a universal formulation of uncertainty relation valid for any
conceivable quantum measurement and the resultant observation (observer) effect
of statistical nature. Owing to its simplicity and operational tangibility, our
general relation is also experimentally verifiable. Our relation violates the
traditional na{\"i}ve bound $\hbar/2$ for the position-momentum measurement
while respecting Heisenberg's original philosophy of the uncertainty principle.
Our error-disturbance relation admits a parallel formulation to our relation
for errors, which also embraces the standard Kennard--Robertson
(Schr{\"o}dinger) relation as a special case; this attains a unified picture of
the three orthodox realms of uncertainty regarding quantum indeterminacy,
measurement, and observation effect within a single framework.
