  Let $D(p,q)$ be the usual knot diagram of the $(p,q)$-torus knot, that is,
$D(p,q)$ is the closure of the $p$-braid $(\sigma_1^{-1} \sigma_2^{-1}...
\sigma_{p-1}^{-1})^q$. As is well-known, $D(p,q)$ and $D(q,p)$ represent the
same knot. It is shown that $D(n+1,n)$ can be deformed to $D(n,n+1)$ by a
sequence of $\{(n-1)n(2n-1)/6 \} + 1$ Reidemeister moves, which consists of a
single RI move and $(n-1)n(2n-1)/6$ RIII moves. Using cowrithe, we show that
this sequence is minimal over all sequences which bring $D(n+1,n)$ to
$D(n,n+1)$.
