Just to quickly recap my own experience of bidding against him. At the end of November last year, this effectively NOS 7A48-7050 Fishing master was listed on Yahoo Japan, as a 1-day auction with an opening bid price of 78,000 Yen. Not cheap, granted, but I thought to myself that if I was ever going to buy one, this mint unworn example had to be it.
https://page.auctions.yahoo.co.jp/jp/auction/p815096150
- 7A48-7050-FishingMaster-YahooJapan-Nov2020-Another-(NOS)-Listing.jpg (190.63 KiB) Viewed 31066 times
It ended up selling for ¥91,800 Yen after 14 bids, equivalent to approx. $881.70 USD / £662.40 GBP, at prevailing rates.
- 7A48-7050-FishingMaster-YahooJapan-Nov2020-Another-Ended-Sold-91800Yen.png (41.93 KiB) Viewed 31066 times
I was the losing bidder.
I bid it as high as 91,000 Yen, before giving up. The auction finishing time was automatically extended by a total of 45 minutes. Whoever I was bidding against seemed determined to win. Their annoying tactic was to leave it until the final seconds of the 5 or 10 minute extension period, before placing their next bid, which of course extended the finishing time once again. 
With hindsight, I wish now I'd carried on slugging it out with them. No doubt it could easily have gone on for an hour or more, but I'm fairly certain now I know who I was bidding against, that even if the bid price had gone over 100,000 Yen, it's unlikely I would have ended up winning. - 7A48-7050-FishingMaster-YahooJapan-Nov2020-Another-Buyee-Outbid-90K.png (111.68 KiB) Viewed 31066 times
So you can probably imagine how absolutely livid I was, when profiteering cross-platform Japanese re-seller jap_t_t_w listed the same unworn 7A48-7050 Fishing Master on eBay on Christmas Day, with a Buy-it-Now price of $2200 !!
https://www.ebay.com/itm/w610-NOS-SEIKO ... 4127114519
- 7A48-7050-FishingMaster-eBay-Dec2020-(Re-seller)-Listing.png (223.82 KiB) Viewed 31066 times
It's not the first time I've seen him pull this stunt either.
There was another similar instance earlier in November. 
Although he's since reduced their prices slightly), both those 7A48-7050 Fishing Masters still currently remain unsold.
https://www.ebay.com/itm/w594-SEIKO-7A4 ... 4085134624
https://www.ebay.com/itm/w610-NOS-SEIKO ... 4127114519
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I may be pre-judging his motives, but it appears this profiteering re-seller is attempting to monopolize the market.
Last week, another 7A48-7050 Fishing Master, in average worn condition, with a short bracelet (only 16cm) was listed by a 'Store' seller, as a 4-day auction with an opening bid price of 1 Yen. Frankly I wasn't really that interested anymore, but added it to my Buyee watching page and bid it up to 10,000 Yen. At lunchtime today, 12:40 UK time, an ending soon notification arrived in my email inbox, reminding me that the auction was due to end in 15 minutes.
- 7A48-7050-FishingMaster-YahooJapan-Feb2020-Ending15Mins.png (136.14 KiB) Viewed 31096 times
I didn't bother taking any screen shots when I first saw the listing on Yahoo Japan, but here's the basic details:
https://page.auctions.yahoo.co.jp/jp/auction/v784446826
1円★希少◎稼働【セイコー/SEIKO】QZ/クオーツ 7A48-7050 フィッシングマスター ムーンフェイズ クロノグラフ メンズ腕時計 A0059157
- 7A48-7050-FishingMaster-YahooJapan-Feb2021-1.jpg (121.29 KiB) Viewed 31095 times
- 7A48-7050-FishingMaster-YahooJapan-Feb2021-2.jpg (243.3 KiB) Viewed 31096 times
- 7A48-7050-FishingMaster-YahooJapan-Feb2021-3.jpg (216.07 KiB) Viewed 31096 times
- 7A48-7050-FishingMaster-YahooJapan-Feb2021-4.jpg (255.25 KiB) Viewed 31096 times
One hour after it was originally scheduled to end (@ 21:55 JST), the current Yahoo Japan auction for a 7A48-7050 Fishing Master is still being automatically extended, due to late bids, with no sign of it ending anytime soon !!
