The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. If the bank, while making a guarantee, agreed that it will immediately pay the deposit requested by the beneficiary without being bound by any terms and conditions of the underlying contract or the performance provision, in a case where a written claim and the document expressly demanded by the beneficiary consistent with the terms and conditions of the payment of the deposit are presented, this is not an ordinary guarantee in relation to the principal obligation, but an ordinary guarantee in relation to the principal obligation, which is independent of the principal obligor, the client and the creditor, and at the request of the beneficiary, only if there is a demand by the beneficiary without defense against the beneficiary on grounds of the underlying relationship.

In this regard, the guarantor of such independent bank guarantee is obliged to pay the amount specified in the letter of guarantee regardless of whether the client bears responsibility for default in relation to the beneficiary, and in this respect, the independent bank guarantee is distinct from the cause relationship between the beneficiary and the client.

However, an independent bank guarantee is not completely excluded from the application of the principle of trust and good faith or the principle of prohibition of abuse of rights. Thus, when it is objectively apparent that the beneficiary makes a claim against the guarantor by abusing the abstract and unmanned character of the bank guarantee even though the beneficiary does not have any right to the guarantor, it is not permissible to constitute an abuse of rights. In such a case, the guarantor may refuse the payment of the deposit upon the beneficiary's request, but it is a abstract and unmanned relation.