Seals were in fact in chronological order until the introduction of the D seal. This was very apparent examining seals on specific prints over time and for prints within series. The reason for overlapping dates below is because of the delay between carving the date on the keyblock and a print actually being published and a seal applied when removed from inventory (a delay of usually months, but up to 8 years and 25 years in cases of Hasui's Ioridani Pass and Cormorant Fishing, respectively).
|11||March 1909-1916. Round2, diameter 10mm approx. Watanabe ワタナベ in katakana.
1915-1947. Round, diameter 6mm approx.3
1947-1989. Round, diameter 6mm to 7mm.4
1989-present. Round, diameter 7mm.
|A||1926-1930. Reads copyright Watanabe Shozaburo (Kako). 版権所有渡邊庄三郎|
|B||1930-March 1932. Reads published by Watanabe. 版元渡邊版画店|
|C1||January 1931-March 1933. Colloquially referred to as the Sausage seal. Type 1 seal never seen after 1933. Reads copyright Watanabe Shozaburo. 版権所有渡邊庄三郎|
|D||December 1933-1941. The Watanabe family seal is followed by kanji reading copyright and not to be reproduced without permission.|
|E||1940-1941. Reads published by Watanabe in Ginza.|
|F||1940-1943. Reads designed by Watanabe in Ginza.|
|G||1941-1944. Reads designed by Watanabe.|
|H||c.1979. Reads copyright Watanabe Tadasu.5 版元銀座渡邊規|
|I||1989-2019. Red colour. Heisei era seal. Indicates a print from older woodblocks, not necessarily original woodblocks. 6|
|J||2012-present. Indicates a reproduction, that is, a print made from newly carved woodblocks. Reads copyright Watanabe Shoichiro. 版権所有渡邊章一郞|
|K||2019-present. Black colour. Reiwa era seal. Indicates a print from older woodblocks, not necessarily original woodblocks. 6|
1 This follows the nomenclature suggested by Watanabe Tadasu in 1982, and updates dates based on new data - new data from recording many thousands of prints and seals in a database, and longitudinal data from block wear and provenance of selected prints.
2 There was also a rare square version of the seal.
3 The round seal isn't especially useful for dating. The round seal continued on most prints until late 1926. For example, early impressions of Hasui's Zojoji Temple in Shiba (1925) featured the round seal. This seal was applied on Hasui's small prints, commissions, and intermittently on large prints in the late-1920s, 1930s and early 1940s. It was applied more frequently from the late 1930s and became the primary seal again from 1947. Note that many prints actually printed in the late 1930s and 1940s were sealed with the round seal and sold post-war.
The round seal continued on Ito Shinsui prints from 1910s to 1960s.
4 Watanabe Shoichiro and leading scholar Shimizu Hisao each stated that the round hanko seal applied on any particular day - its size and colour - was essentially random. Prints verified from the late 1940s usually had 6.5mm diameter although there were outliers ranging from 5.5mm (without the outer circle) to 7.1mm.
The mistaken belief directly correlating older prints and smaller seals has been attributed to Westerners misunderstanding how hanko seals were made and applied by Japanese. Prints with round 6mm seals were sold by the publisher from 1915 to 1989, after which time the publisher standardised size to 7mm.
It is quite common to see Hasui prints with round 6mm seal on modern paper (Iwano Ichibei) and with modern printmaking techniques (original baren suji-zuri replaced with goma-zuri gradations) suggesting that such prints were much later prints, probably 1980s.
The round seal on prints with Heisei or Reiwa seals typically measures 7.3mm.
5 Various artists and limited edition prints. On Hasui commemorative edition prints, commissioned by Osaka Mainichi, it was accompanied with round 7mm seal.
6 Prints on which this seal appears have usually had many, if not most, of their colour blocks recarved. Some prints such as Hasui's Snow at Shiba Park and Toyonari are reproductions with new keyblocks and colour blocks. Watanabe describes these as atozuri, which translates to later prints (as opposed to shokizuri, early prints).
Note 1: Printer seals
|P1||1938-1944. Reads master printer Ono Gintaro. 摺師斧銀太郎|
|P2||1943-1951. Reads printer Ono Gintaro (1884-1965).|
Gintaro was printer for Watanabe from 1911 to 1956 approx.
Note 2: Address labels
|L1||1916-September 1923 (-Great Kanto earthquake). No. 11 Gorobei-cho, Kyobashi-ku, Tokyo.|
|L2||November 1925-March 1930. No. 14 Hiyoshi-cho, Kyobashi-ku, Tokyo. 四十町吉日区橋京市東京|
|L3||March 1930-c.1970. No. 9 Nishi 8-chome, Ginza, Tokyo. 九 ノ八西座銀区橋京市東京|
|L4||c.1970-c.1995. 6-19 Ginza 8-chome, Tokyo. 東京都中央区銀座8-6-19|
Diamond-shaped labels adhered to the verso of prints, on folders, or on frames.
Note 3: Miscellaneous seals
|M1||1915-1960, 1979. Watanabe's personal seal. Erroneously referred to as the Gift seal. Watanabe わたなべ in hiragana.|
|M2||1921. Hiroshi Yoshida prints. The Watanabe family seal is followed by kanji reading publisher.|
|M3||1925-1928. Natori Shunsen prints. Reads published by Watanabe. 渡邊工|
|M4||c.1922-c.1937. Test print, tameshizuri 試摺|
|M5||After 1928. Gift seal, shintei 進呈|
|M6||1957, 1979. Final brush seal, zeppitsu 絶筆|
|M7||After 1930. Blue stamp on verso.|
|M8||1970s. Label adhered to verso of prints or frames.|
M1 may be stamped on the front or verso - when on the front it was a substitute for the round seal. M4 indicates a trial or proof print. M5 indicates a gift or presentation print. The stamp may be on the front or reverse, and may be accompanied by an inscription. M6 indicates Hasui's memorial print. M7 is probably an export stamp, similar to the verso stamp "Made in Japan" that appeared on prints between 1921 and circa 1955.
Note 4: Reproductions
Reproductions with seal J were very well carved and create high quality impressions. In many ways these are superior prints to those with seals I and K that may retain some link to original woodblocks. Those weathered and worn woodblocks, especially those first issued in the 1920s or 1930s, result in quite poor impressions.
Note 5: Fake and forged seals
Unscrupulous dealers have been known to fake seals A, B (including a variation, hanmoto Watanabe Shozaburo), C, D, E and F. Their aim of course is to make a print appear older increasing its perceived scarcity and market value.
It is recommeded to always examine the impression as the difference between an early impression and later impression is quite obvious. Early impressions tend to have clear and sharp lines. Later impressions from worn woodblocks can be quite blurred in appearance. A later impression with early seals is not plausible. It has been noted recently by various sources (June 2023), including Egenolf Gallery, that the Doi family or printer Yamamoto are publishing later impressions with implausibly early seals.
It is recommended to be sceptical when two seals - double seals - appear on a print. This may be legitimate, however, it is unusual and it's possible that a fake seal was added to make the print appear older. Watanabe Shoichiro and the Ukiyo-e Dealers Association of Japan recently warned that Hasui prints were sold in Japan with newly forged seals. Seals I and K had been removed from the margin and replaced with earlier copyright seals such as C and D (August 17, 2022).
It is recommended to be especially sceptical when Watanabe seals appear on a print originally made by another publisher such as Doi Sadaichi.
Later impressions missing all seals often sell for significant premiums at auction. These prints are typically unauthorized prints made by the printer and sold by the printer or his estate. A printer was in fact dismissed for selling unauthorized Hasui prints in 1995 for ¥5000 each. Significant premiums at auction require at least two bidders - at least two bidders possibly intending on applying forged seals for profit.