
Remark 10.150.4. We can also construct $R^{sh}$ from $R^ h$. Namely, for any finite separable subextension $\kappa \subset \kappa ' \subset \kappa ^{sep}$ there exists a unique (up to unique isomorphism) finite étale local ring extension $R^ h \subset R^ h(\kappa ')$ whose residue field extension reproduces the given extension, see Lemma 10.148.7. Hence we can set

$R^{sh} = \bigcup \nolimits _{\kappa \subset \kappa ' \subset \kappa ^{sep}} R^ h(\kappa ')$

The arrows in this system, compatible with the arrows on the level of residue fields, exist by Lemma 10.148.7. This will produce a henselian local ring by Lemma 10.149.7 since each of the rings $R^ h(\kappa ')$ is henselian by Lemma 10.148.4. By construction the residue field extension induced by $R^ h \to R^{sh}$ is the field extension $\kappa \subset \kappa ^{sep}$. Hence $R^{sh}$ so constructed is strictly henselian. By Lemma 10.149.2 the $R$-algebra $R^{sh}$ is a colimit of étale $R$-algebras. Hence the uniqueness of Lemma 10.149.6 shows that $R^{sh}$ is the strict henselization.

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