歴史時代の資料研究には精度の高い年代測定が求められるため，特にウィグルマッチ法（wiggle-matching method）による炭素14年代測定が有効である。本研究は，ウィグルマッチ法による炭素14年代測定（14Cウィグルマッチ法）を，具体的に三つの国指定重要文化財の民家，神奈川県関家住宅・兵庫県箱木家住宅・広島県吉原家住宅に適用した事例の報告である。その意義については本課題のその1で述べられている。ここでは，方法論的技術的な観点を中心に記述した。重要文化財関家住宅では，主屋3点および書院1点から得られた旧柱材4点で測定を行った。これらの柱材からそれぞれ年輪5－7試料を採取し，それぞれについて炭素14濃度測定を行い，ウィグルマッチ法で最外層の年代を推定した。これらは加工によって辺材部分を欠いていると考えられるが，この部分の年輪数を仮定することで，主屋の2点が17世紀前半，1点は16世紀，また，書院は17世紀中頃の材と推定された。同様な方法で，重要文化財箱木家住宅の柱材（年輪数11，芯持材で当初材）は13世紀末から14世紀前葉，あるいは14世紀後葉，また板材（現場で微小試料を採取）は14世紀中葉あるいは15世紀前葉と推定された。すなわち箱木家は少くとも14世紀ころの建造と考えるのが妥当である。重要文化財吉原家住宅では，2点の柱材のうち1点は18世紀初頭，別の1点は16世紀あるいは17世紀中葉を示す結果となった。以上みたように14Cウィグルマッチ法は古民家の建築年代を従来にない精度で絞り込める可能性を示す一方で，解体修理などから得られた情報（当初材の識別など）との整合性の把握など，総合的な取り組みの重要性，また，資料群の中に樹皮に近い資料を確保するべきであること，測定データの一層の精度向上を企てるべきであるなどの課題が指摘された。

Precise dating is required when studying materials from historical periods. The ¹⁴C wiggle matching is a method for precision dating used in radiocarbon dating, and particularly useful for studying wood from which a number of tree-rings with known time intervals are available.The research described here applied the ¹⁴C wiggle matching to three old residences, and then examined their respective construction dates from a methodological perspective. The residences, all of which have been designated important cultural properties by the government, are the Seki residence in Kanagawa Prefecture, the Hakogi residence in Hyogo Prefecture, and the Yoshiwara residence in Hiroshima Prefecture. For the Seki residence measurements were made on four old wooden pillars, of which three were obtained from the main residence and one from the study. Five to seven tree-ring samples for each were taken from these wood which were then each measured using carbon-14 dating. Next, we used the wiggle matching method to estimate the dates of the outermost layers. While it is believed that these pieces were missing the sapwood portion because of processing, by presuming the number of tree rings for this portion, it was estimated that two pieces from the main residence date back to the first half of the 17th century, while one piece dates back to the 16th century, a date which suggests the possibility of the reuse of old wood. We estimated that the piece from the study dates back to the middle of the 17th century.The same method was applied to wood from pillars (original wood with core and 11 tree-rings) from the Hakogi residence. They dated from either the end of the 13th century through the early 14th century or the latter part of the 14th century. Minute samples obtained from boards at the residence site put this wood at either the middle of the 14th century or the early part of the 15th century. Accordingly, it is correct to say that the Hakogi residence was built befor or during the 14th century.Dating of two pieces of wood from pillars of the Yoshiwara residence revealed that one dated from the beginning of the 18th century and the other from the 16th century to the middle of the 17th century.As shown above, the ¹⁴C wiggle matching method shows potential for narrowing down construction dates for old residences with unprecedented accuracy. On the other hand, it also raised a number of issues, including the importance of undertaking a comprehensive study that includes ascertaining consistency with information obtained from other sources such as dismantling and repairs (identification of the initial wood, etc), the need to obtain materials close to the bark among the set of materials, and the need to try to improve the precision of measurement data.

source:https://www.rekihaku.ac.jp/outline/publication/ronbun/ronbun6/index.html#no137