system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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Risks and War Risk. 11. PAYMENT: Under Letter of Credit or T/T: Under the Letter of Credit: The Buyer shall open an irrevocable letter of credit with the bank within 30 days after signing the contract, in favor of the Seller, for 100% value of the total contract value. The letter of credit should state that partial shipments are allowed. The Buyer's agent agrees to pay for the goods in accordance with the actual amount of the goods shipped. 80% of the system value being shipped will be paid against the documents stipulated in Clause 12.1. The remaining 20% of the system value being shipped will be paid against the documents stipulated in Clause 12.2. The Letter of Credit shall be valid until 90 days after the latest shipment is effected. Under the T/T The trustee of the buyer remitted the goods to the seller by telegraphic transfer in batches as agreed upon after signing each order. 12. DOCUMENTS: 12.1 (1) Invoice in 5 originals indicating contract number and Shipping Mark (in case of more than one shipping mark, the invoice shall be issued separately). (2) One certificate of origin of the goods. (3) Four original copies of the packing list. (4) Certificate of Quality and Quantity in 1 original issued by the agriculture products base. (5) One copy of insurance coverage (6) Copy of cable/letter to the transportation department of Buyer advising of particulars as to shipment immediately after shipment is made. 3 Source: LOHA CO. LTD., F-1, 12/9/2019 12.2 (1) Invoice in 3 originals indicating contract number and L/C number. (2) Final acceptance certificate signed by the Buyer and the Seller. 13. SHIPMENT: CIP The seller shall contract on usual terms at his own expenses for the carriage of the goods to the agreed point at the named place of destination and bear all risks and expenses until the goods have been delivered to the port of destination. The Sellers shall ship the goods within the shipment time from the port of shipment to the port of destination. Transshipment is allowed. Partial Shipment is allowed. In case the goods are to be dispatched by parcel post/sea-freight, the Sellers shall, 3 days before the time of delivery, inform the Buyers by cable/letter of the estimated date of delivery, Contract No., commodity, invoiced value, etc. The sellers shall, immediately after dispatch of the goods, advise the Buyers by cable/letter of the Contract No., commodity, invoiced value and date of dispatch for the Buyers. 14. SHIPPING ADVICE: The seller shall within 72 hours after the shipment of the goods, advise the shipping department of buyer by fax or E-mail of Contract No., goods name, quantity, value, number of packages, gross weight, measurements and the estimated arrival time of the goods at the destination. 15. GUARANTEE OF QUALITY: The Sellers guarantee that the commodity hereof is complies in all respects with the quality and specification stipulated in this Contract. 16. CLAIMS: Within 7 days after the arrival of the goods at destination, should the quality, specification, or quantity be found not in conformity with the stipulations of the Contract except those claims for which the insurance company or the owners of the vessel are liable, the Buyers, on the strength of the Inspection Certificate issued by the China Commodity Inspection Bureau, have the right to claim for replacement with new goods, or for compensation, and all the expenses (such as inspection charges, freight for returning the goods and for sending the replacement, insurance premium, storage and loading and unloading charges etc.) shall be borne by the Sellers. The Certificate so issued shall be accepted as the base of a claim. The Sellers, in accordance with the Buyers' claim, shall be responsible for the immediate elimination of the defect(s), complete or partial replacement of the commodity or shall devaluate the commodity according to the state of defect(s). Where necessary, the Buyers shall be at liberty to eliminate the defect(s) themselves at the Sellers' expenses. If the Sellers fail to answer the Buyers within one weeks after receipt of the aforesaid claim, the claim shall be reckoned as having been accepted by the Sellers. 4 Source: LOHA CO. LTD., F-1, 12/9/2019 17. FORCE MAJEURE: The Sellers shall not be held responsible for the delay in shipment or non-delivery, of the goods due to Force Majeure, which might occur during the process of manufacturing or in the course of loading or transit. The Sellers shall advise the Buyers immediately of the occurrence mentioned above and
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Extract the exact clause related to "Effective Date" from the excerpt above.