Iyo no Jo Minamoto Munetsugu worked at Isahaya in Hizen as a pupil of the first-generation Tadayoshi, and the published sources rank him with that founder as one of the pioneers of early-modern Hizen forging. He belongs to a school remembered for the calmest of refinements, the fine konuka-hada and quiet suguha that Nabeshima patronage made the Hizen standard, and within it he is the deliberate exception. Where the main line tempered a straight hamon that turns into a small round ko-maru, Munetsugu forged a vigorous irregular temper in an emphasized Soshu-den manner, and the commentaries return again and again to that contrast as the thing that fixes a blade in his hand. The early name Muneyasu, which the old reference works treated as that of a disciple of the first Iyo no Jo, is held in the prevailing view to be the first signature of the second generation, named by the lord Nabeshima Katsushige in the ninth month of Kan'ei 9.

His characteristic hand is a midareba built on gunome and notare, conspicuous for the pointed togariba mixed within it. The published sources name the togari as a hallmark of his varied temper, and it is the Soshu-den point, not the soft clove-head of Bizen, that separates him from the orthodox Hizen suguha. Over the temper run vigorous sunagashi and frequent kinsuji, the nioi deep and the nie thick, with tobiyaki, yubashiri and muneyaki breaking out above the yakigashira; the upper half characteristically turns more floridly than the lower. The boshi is the surest tell of all. The mainline Hizen point runs straight and rounds in ko-maru, but Munetsugu's almost always enters midare-komi and sweeps back in hakikake, at times flame-like, so that the NBTHK can say of one of his katana that the irregular boshi makes his work unmistakable among other Hizen blades[[c:1]].

The jigane carries the school's fineness without its restraint. He forges a fine itame, often a closely packed ko-itame that takes on a flowing tendency, the surface covered with thick ji-nie and threaded with chikei; on the broader pieces the grain stands a little, and a touch of larger hada appears. The steel reads as the refined Hizen material the published sources describe as excellent in quality, but it is made to serve a Soshu-den temper rather than a quiet suguha, and the ji and ha together are read as richly covered in nie and assertive in spirit. Even the tang is part of the portrait: he thins the flesh on the edge side to give a tanago-bara fish-belly tendency, and against the Hizen habit of signing the ura he cuts a bold long signature on the sashi-omote, in fine chisel yet large and expansive, a hand the commentaries call distinctive on sight.

The corpus divides cleanly by name across two generations who share a single manner. The first generation signs Munetsugu, most fully as Iyo no Jo Minamoto Munetsugu of Hizen, and the published record makes him the maker of the line's finest pieces. The second generation signs the early name Muneyasu before assuming the Iyo no Jo Munetsugu title, and his blades, few in number, are valued as much for what they settle as for their quality. The Muneyasu commentaries quote the Shinto Bengi, which says only 「伊予掝(初代)門人ならむか」, perhaps a disciple of the first Iyo no Jo, and the Shinto Ichiran and Kokon Kajibiko, which likewise treat him as that disciple, then set the modern reading against them: that Muneyasu is the second generation's first signature, corroborated by a surviving naming warrant from Nabeshima Katsushige. The reverse sujikai file marks are the other generational divider the texts name. What does not change between the two is the workmanship, which the published sources treat as a single shared range, so that a Muneyasu and a Munetsugu read alike to the eye.

That shared range has a stated model. The published sources say the first generation customarily took old Shizu works as his pattern, and they describe the Muneyasu pieces as aiming at Shizu in the same Soshu-den style, the fine nie giving the nioiguchi a soft, luminous brightness and an unforced, archaic taste. The model places Munetsugu against his own school by his own grounded traits rather than by anyone else's. His is the bright, nie-laden Soshu-den midare with conspicuous togari and an irregular swept boshi, set inside the very school whose name stands for refined suguha, and the resulting individuality is exactly what the commentaries mean when they call him the most distinctive of the Hizen smiths and his work unmistakable among them. The togari hallmark and the midare-komi boshi carry across both generations, which is why the second generation's Muneyasu blades are read as confirmation of the first generation's hand rather than as a departure from it.

He is a Jo-jo saku smith with a thin but high record: one katana in the Tokubetsu Juyo and ten in the Juyo, against no National Treasure and no Important Cultural Property, so that the designated blades on record number around a dozen and reach the market only rarely. The summit of that record, and of his life's work, is the Tokubetsu Juyo katana forged through the silver that the third shogun Tokugawa Iemitsu bestowed within Kyoto on his Kan'ei 11 visit to the capital; Nawa Sotan, of the lineage of Nawa Doen, a senior retainer of Tokugawa Yorinobu of Kii, applied part of that bestowed silver to commission it, and the order inscription with its date of 1634 makes the piece, in the words of the published commentary, his finest achievement across his lifetime[[c:2]] and a document of exceptional value. Beyond that named sword, provenance is sparse and best left as recorded rather than embellished; no current museum or shrine holding is on record for his blades. For a collector, a Munetsugu or a Muneyasu is among the more individual things early Hizen can offer, a Soshu-den exception inside a suguha school, encountered from time to time and with patience among the Juyo blades, a landmark of the line when one appears.

Iyo no Jo Minamoto Munetsugu worked at Isahaya in Hizen as a pupil of the first-generation Tadayoshi, and the published sources rank him with that founder as one of the pioneers of early-modern Hizen forging. He belongs to a school remembered for the calmest of refinements, the fine konuka-hada and quiet suguha that Nabeshima patronage made the Hizen standard, and within it he is the deliberate exception. Where the main line tempered a straight hamon that turns into a small round ko-maru, Munetsugu forged a vigorous irregular temper in an emphasized Soshu-den manner, and the commentaries return again and again to that contrast as the thing that fixes a blade in his hand. The early name Muneyasu, which the old reference works treated as that of a disciple of the first Iyo no Jo, is held in the prevailing view to be the first signature of the second generation, named by the lord Nabeshima Katsushige in the ninth month of Kan'ei 9.

His characteristic hand is a midareba built on gunome and notare, conspicuous for the pointed togariba mixed within it. The published sources name the togari as a hallmark of his varied temper, and it is the Soshu-den point, not the soft clove-head of Bizen, that separates him from the orthodox Hizen suguha. Over the temper run vigorous sunagashi and frequent kinsuji, the nioi deep and the nie thick, with tobiyaki, yubashiri and muneyaki breaking out above the yakigashira; the upper half characteristically turns more floridly than the lower. The boshi is the surest tell of all. The mainline Hizen point runs straight and rounds in ko-maru, but Munetsugu's almost always enters midare-komi and sweeps back in hakikake, at times flame-like, so that the NBTHK can say of one of his katana that the irregular boshi makes his work unmistakable among other Hizen blades[[c:1]].

The jigane carries the school's fineness without its restraint. He forges a fine itame, often a closely packed ko-itame that takes on a flowing tendency, the surface covered with thick ji-nie and threaded with chikei; on the broader pieces the grain stands a little, and a touch of larger hada appears. The steel reads as the refined Hizen material the published sources describe as excellent in quality, but it is made to serve a Soshu-den temper rather than a quiet suguha, and the ji and ha together are read as richly covered in nie and assertive in spirit. Even the tang is part of the portrait: he thins the flesh on the edge side to give a tanago-bara fish-belly tendency, and against the Hizen habit of signing the ura he cuts a bold long signature on the sashi-omote, in fine chisel yet large and expansive, a hand the commentaries call distinctive on sight.

The corpus divides cleanly by name across two generations who share a single manner. The first generation signs Munetsugu, most fully as Iyo no Jo Minamoto Munetsugu of Hizen, and the published record makes him the maker of the line's finest pieces. The second generation signs the early name Muneyasu before assuming the Iyo no Jo Munetsugu title, and his blades, few in number, are valued as much for what they settle as for their quality. The Muneyasu commentaries quote the Shinto Bengi, which says only 「伊予掝(初代)門人ならむか」, perhaps a disciple of the first Iyo no Jo, and the Shinto Ichiran and Kokon Kajibiko, which likewise treat him as that disciple, then set the modern reading against them: that Muneyasu is the second generation's first signature, corroborated by a surviving naming warrant from Nabeshima Katsushige. The reverse sujikai file marks are the other generational divider the texts name. What does not change between the two is the workmanship, which the published sources treat as a single shared range, so that a Muneyasu and a Munetsugu read alike to the eye.

That shared range has a stated model. The published sources say the first generation customarily took old Shizu works as his pattern, and they describe the Muneyasu pieces as aiming at Shizu in the same Soshu-den style, the fine nie giving the nioiguchi a soft, luminous brightness and an unforced, archaic taste. The model places Munetsugu against his own school by his own grounded traits rather than by anyone else's. His is the bright, nie-laden Soshu-den midare with conspicuous togari and an irregular swept boshi, set inside the very school whose name stands for refined suguha, and the resulting individuality is exactly what the commentaries mean when they call him the most distinctive of the Hizen smiths and his work unmistakable among them. The togari hallmark and the midare-komi boshi carry across both generations, which is why the second generation's Muneyasu blades are read as confirmation of the first generation's hand rather than as a departure from it.

He is a Jo-jo saku smith with a thin but high record: one katana in the Tokubetsu Juyo and ten in the Juyo, against no National Treasure and no Important Cultural Property, so that the designated blades on record number around a dozen and reach the market only rarely. The summit of that record, and of his life's work, is the Tokubetsu Juyo katana forged through the silver that the third shogun Tokugawa Iemitsu bestowed within Kyoto on his Kan'ei 11 visit to the capital; Nawa Sotan, of the lineage of Nawa Doen, a senior retainer of Tokugawa Yorinobu of Kii, applied part of that bestowed silver to commission it, and the order inscription with its date of 1634 makes the piece, in the words of the published commentary, his finest achievement across his lifetime[[c:2]] and a document of exceptional value. Beyond that named sword, provenance is sparse and best left as recorded rather than embellished; no current museum or shrine holding is on record for his blades. For a collector, a Munetsugu or a Muneyasu is among the more individual things early Hizen can offer, a Soshu-den exception inside a suguha school, encountered from time to time and with patience among the Juyo blades, a landmark of the line when one appears.