《新定書儀鏡》有〈通婚函書〉與〈答函書〉兩封婚書，先由男方致書禮請，女方再答書許訖，為官宦之家所使用的單書範本。通婚書需以按一定規格製作的禮函裝載，男家遞交、女家接受時均有儀節。男家同時將婚書與聘財送往女家，可知當時六禮只有納徵與親迎兩禮。婚書實際上由六禮版文之納采版文蛻變而來，六禮版文、婚書與禮函間的比較更能清楚定位三者的關係。從六禮版文至婚書的演變則歷經三個步驟。

The engagement letters in XinDingShuYiJing--“proposal letter” by finance family and “consent letter” by finance family, are “DanShu” style examples for mandarinate family. Proposal letter should be placed in a wooden case which is made with specification, while certain ceremony of delivery and receival of the wooden case were hold. As the finance family sent the bride price together with the proposal letter, it shown that the six marriage process was simplified to two marriage process at that time. Engagement letter was developed from the board letter of first marriage process. The comparison between boards letters of the six marriage process, engagement letter and the wooden case exhibits their relationship clearly. There were three steps during the mutation of board letters of the six marriage process to engagement letter.