The number of States Parties had reached 194 as of July 2020. Japan became a party to the Convention in 1992. The standardization of the conservation of cultural heritage started in Europe, mainly for stone masonry structures. In other regions, such as Japan in Asia, there exists ancient temples of wooden structures that were constructed more than 1000 years ago and are treated by different methods for their conservation. In 1996, the experts of ICOMOS gathered in Nara and discussed how to apply the principles of the conservation to other regions and published the Nara Document of Authenticity. The Nara Document of Authenticity recognizes the various materials and structures of heritage structures that have been preserved by different methods developed by each region. The Nara Document of Authenticity further states that the diversity of culture and heritage in our world is an irreplaceable source of spiritual and intellectual richness for all mankind. At present, despite these charts, there is a lack of shared international compulsory rules, except the principles of authenticity--each country has its own rules for conservation of cultural heritage and guidelines for the evaluation and reduction of seismic risk for cultural heritage buildings, to be followed in conservation works. The authenticity of the heritage structure to be preserved must be studied on forms and design, materials and substance, use and function, traditions and techniques, location and setting, and other internal and external factors. ISO 13822: Bases for design of structures--assessment of existing structures was discussed to include the heritage structure in 2005 for 5 years. In 2010, the international standard of the restoration of heritage structure was added to the ISO 13822-2010 as Annex I Heritage Structure. The Annex I Heritage Structure refers conservation of the authenticity of foundations as follows: From the point of view of conservation, foundations are not different from the rest of the structure and should be assessed and rehabilitated, taking into consideration their heritage value. This involves the requirement to identify their authenticity and character-defining elements. The foundation parts of underground surfaces have been historically neglected in the conservation of heritage structures. The restoration work for the leaning Pisa Tower is one of the good examples to learn from in relation to the authenticity and foundations. The last restoration work of the Pisa Tower was successfully completed, and it re-opened to the public in December 2001 after being closed in 1990. Several methods, such as soil extraction, grouting, and pile foundation may be available to stop or to decrease the rate of leaning (Figure 1). Among these methods, soil extraction was selected after a few trials of different approaches, without any discussion of the authenticity of the foundation. The main cause of the tower's incline was the direct shallow foundation on the soft ground with thick, soft clay layers. The character-defining elements of the authenticity of the foundation are identified as follows:  
1. Soft clay layers of the site ground. 2. Shallow direct foundation. If the base soil had been grouted, or the long pile foundation had been introduced, the above-mentioned characters of the authenticity of the foundation would have been completely lost. The integrity of the foundation of the Pisa Tower were to be referred to as being lost. The reality was that the soil extraction was selected after trials of some other methods. Adapting the soil extraction method resulted in keeping the character-defining elements of the authenticity, which resulted in keeping the integrity of the foundation system without any modification. It was very rare case of successful restoration of the foundation system without any discussion of the authenticity. The authenticity of the heritage structure should be discussed before evaluation and before selecting any countermeasures for the restoration.