In Gentoku 1 (1329), in the twelfth month, Naotsugu (直次) of Bitchū signed a small hira-zukuri tantō "Bitchū-shū jū Sahyōe-no-jō Naotsugu"[[c:1]] with the date cut on the reverse, and the NBTHK calls it a fine piece that demonstrates the smith's high technique[[c:2]]. He belongs to the Aoe school of Bitchū, which forged along the lower reaches of the Takahashi river. The published sources divide its production in two: work to about the middle of Kamakura is called Ko-Aoe, and what follows, on into Nanbokuchō, simply Aoe. The Meikan places Naotsugu's activity around the Karyaku era (1326-29); he styled himself Saemon-no-jō and Sahyōe-no-jō, and together with Yoshitsugu he is counted among the representative smiths of the school in the passage from the very end of Kamakura into the opening of Nanbokuchō. His base, as the published record says of the Aoe smiths of this time, is suguha, with many of his blades built fundamentally upon it.
What distinguishes the hand is a controlled chū-suguha rather than the flamboyant chōji of an earlier Bizen. The nioiguchi tightens and brightens, ko-gunome and small angular gunome enter the temper, and faint ashi run toward the base with the reverse slant the school is known for, the saka-ashi that the published sources read as the mark of so-called Sue-Aoe. On the widest of his katana the edge is a naka-suguha with a tight nioiguchi, saka-ashi, ko-ashi and yō, and the nioiguchi is bright and clear; the bōshi rises a little before its return, a slight tsukiage that ends in a pointed turn. He keeps the suguha quiet and lets the jigane and the slant carry the work, and on the Kitaguchi katana the judges find in all of these points the characteristic features of this craftsman and his school[[c:3]].
The jigane shows the Bitchū steel at full strength. A ko-itame mixed with mokume tightens into the so-called chirimen-hada, the crêpe-like surface texture of the school, and through it run the patchy jifu and the clear sumihada patches that are among Aoe's surest tells. On the tantō the forging packs down finely, thick ji-nie gathers, and a faint midare-utsuri rises across it; on the unsigned katana the grain stands more openly, with sumihada mixed in and a rather coarse nie on the edge. The temper on the Gentoku tantō is carried down into the ha-machi, a yakikomi the judges single out, and the bright, clear sharpness of its nioiguchi is what they note above all, the hardened edge keeping its line tight and luminous[[c:4]]. The bōshi runs straight or with a shallow notare and turns back in a ko-maru or, more characteristically, with the tip drawn to a point.
His surviving work falls into two registers by form. The signed and dated pieces are the documentary core: the Gentoku 1 tantō headed by the Sahyōe-no-jō title, ubu with the long mei cut by a slender chisel and the date on the reverse, and the wide-bodied katana signed "Bitchū no kuni jūnin Naotsugu saku," their long signatures preserved through shortening by being folded back into an orikaeshi-mei. The published sources note that among his works the signatures including the Sahyōe-no-jō title are rare[[c:5]], the surviving examples of that type carrying dates of Gentoku, Shōkei and Kenmu, so the office title and the year together fix both the man and the moment. The second register is the shortened tachi attributed to him by sight, ō-suriage and mumei or with only a fragment of the province inscription left at the tang tip; here the faint, reverse-slanting ko-ashi on a standard chū-suguha are read as the well-expressed mark of Sue-Aoe, the attribution and the period alike judged secure. The Meikan reads a first and a second generation under the name, the second dated Ryakuō into Enbun, and the early designations follow it; the modern texts instead describe one Naotsugu "active from late Kamakura into early Nanbokuchō"[[c:6]], and the record is kept here as one.
What sets him apart within the school is stated in his own work rather than borrowed from a comparison. The published sources call one tantō a clear expression of the characteristics of the late-Kamakura Aoe school, Naotsugu in particular[[c:7]], and another the very type of the late-Kamakura suguha Aoe blade[[c:8]], the ko-maru bōshi and the steep ō-sujikai filing named as the school's own viewing points. His chū-suguha with its quiet reverse slant stands just before the school's Nanbokuchō peak, where the suguha turns to nioi-deki and the characteristic saka-chōji-midare appears; his manner is the standard Sue-Aoe work that the peak would carry further. On the unsigned katana attributed to him the judges find the jigane good and the workmanship good[[c:9]], allowing only that the nioiguchi shows a slight cloudiness, and they note that the former tachi silhouette and the workmanship make both the period assessment and the attribution untroubled. The bare two-character mei and the ō-sujikai file marks of the Niigata tantō are called typical, the signature characters and the filing alike following the established conventions of the school[[c:10]].
The record that survives him is almost wholly in the designated tiers. Twenty of his works carry an official designation: two Important Cultural Properties, three prewar Jūyō Bijutsuhin, five Tokubetsu-Jūyō and ten Jūyō; Fujishiro rates him Jō-saku. The published sources praise the quality of execution repeatedly, the Kitaguchi katana judged thoroughly healthy in both ji and ha[[c:11]] and the Tokubetsu-Jūyō katana a piece that clearly expresses the style of the Aoe school of this period, of particularly excellent workmanship[[c:12]]. His two Important Cultural Properties rest in institutional care, among them the Kyoto National Museum, and provenance recorded against his Jūyō Bijutsuhin runs through the Owari Tokugawa and Tokugawa Iesato; beyond those, what a collector may realistically encounter is one of the Tokubetsu-Jūyō or Jūyō pieces: a signed and dated tantō in which the late-Kamakura Aoe manner is set down whole, or a shortened katana whose folded-back signature still names the smith. They come to light only from time to time, and a signed and dated example, ubu and clear in both its characters and its file marks, is the kind of thing the published sources themselves treat as material of high documentary value.
