Kochi prefectural Technology Center has five missions as administrative policies, major one of them is to develop high performance papers for repairing cultural assrts, in order to make contribution to Japanese culture using traditional Japanese paper. This article presents one of our activities. In the case of repairing paper-form cultural assets, two totally distinct approaches have been adopted in the East and in Europe and America. Eastern method is to simply exchange the support paper on the back for additional strength while keeping main body as it is. A variety of high performance papers have been used for such types of repair. On the other hand, in Europe and America, old books cmposed of papers printed on both sides must be repaired. Several examples for high performance papers used for reoair in libraries and museums throughout Europe are introduced. At last, I would present a joint research project for repair of paper-form cultural assets that we have taken part in, the principle of paper splitting method and how to reinforce the paper samples using this method.