Governor.
Well done, this is the one I had in mind!
At the start of my turn, my hand consists of five copies of the same card and nothing else.
Band of Misfits? Aka "Hand of Misfits".
I love "Hand of Misfits", but I can't see the sequence of moves that would give you two Provinces. I thought maybe Worker's Village then Bridge until I remembered the wording on BoM is "less than it" rather than "up to $4".
After some thought, I can easily see how you could get two Provinces with a HoM, so here's a new puzzle. How many Provinces can you get starting with only a Hand of Misfits (no Duration/Mat/Tokens/Events/Prince)? I think the answer is at least 5.
I'd expect it to be possible to piledrive Colonies, maybe more. Are we assuming no cards in deck/discard either?
Yep, same starting point as before. And yeah I think it's possible to gain at least 8 Colonies and 8 Provinces, at least with perfect shuffle luck.
No perfect shuffle luck needed. I'm sure that starting with 5 BoM is more than adequate to launch into something akin to CelestialChameleon's solution to gaining the entire Supply. However, I'm doing this on the fly and I'm not great with these big chains, so I'm not going to be nearly so optimal.
Kingdom:
Squire, Scrying Pool, Develop, Fortress, Ironworks, Procession, Band of Misfits, Highway, Border Village, King's CourtBoM1-as-Procession (0 actions)
BoM2-as-Procession
BoM3-as-Procession
BoM4-as-Squire
+2 buys ($1, 3 buys, including the default one)
BoM4-as-Squire again
+2 buys ($2, 5 buys)
Trash BoM4-as-Squire, gain Scrying Pool (SP1), gain Border Village (BV1) and BoM6
BoM3-as-Procession again
BoM5-as-Fortress (reshuffle, draw a card, 2 actions)
BoM5-as-Fortress again (draw a card, 4 actions)
Trash BoM5-as-Fortress (it returns to your hand), gain BV2 and BoM7
Trash BoM3-as-Procession, gain BV3 and BoM8
BoM2-as-Procession again
BoM5-as-Fortress (draw a card, 6 actions)
BoM5-as-Fortress again (reshuffle, draw a card, 8 actions)
Trash BoM5-as-Fortress (it returns to your hand), gain BV4 and BoM9
Trash BoM2-as-Procession, gain BV5 and BoM10
Scrying Pool to draw my deck.My hand is now 5 Border Villages and 6 BoM (5-10).
I have 8 actions remaining, $2, 5 buys total.
BoM5-as-Procession (7 actions)
BoM6-as-Procession
BoM7-as-Procession
BoM8-as-Procession
BoM9-as-Squire
+2 buys ($3, 7 buys)
BoM9-as-Squire again
+2 buys ($4, 9 buys)
Trash BoM9-as-Squire, gain SP2, BV6 and Fortress
BoM8-as-Procession again
BV1 (reshuffle, draw a card, 9 actions)
BV1 again (draw a card, 11 actions)
Trash BV1, gain King's Court (KC1)
Trash BoM8-as-Procession, gain BV7 and Develop (Dev1)
BoM7-as-Procession again
BV2 (draw a card, 13 actions)
BV2 again (reshuffle, draw a card, 15 actions)
Trash BV2, gain KC2
Trash BoM7-as-Procession, gain BV8 and Dev2
BoM6-as-Procession again
BoM10-as-Squire
+2 buys ($5, 11 buys)
+2 buys ($6, 13 buys)
Trash BoM10-as-Squire, gain SP3, BV9 and Dev3
Trash BoM6-as-Procession, BV10 and Highway (HW1)
Play SP2 to draw deck.My hand is now 1 Scrying Pool, 1 Fortress, 1 Highway, 2 King's Court, 3 Develop, 8 Border Village (3-10).
I have 15 actions remaining, $6, 13 buys total.
KC1 (14 actions)
KC2
Dev1 on BV3-5, gaining HW2-4 and KC3-5
KC2 again
Dev2 on BV6-8, gaining HW5-7 and KC4-8
KC2 final time
Dev3 on BV9, BV10 and Fortress, gaining HW8-10, KC9-10 and Ironworks
Play SP3 to draw deck.My hand is now 1 Fortress, 10 Highway, 8 King's Court, 1 Ironworks.
I have 14 actions remaining, $6, 13 buys total. At this point I have no idea why I'm still tracking actions. Turns out I didn't need to track money either (I was thinking earlier that I might end up buying those $1 Colonies).
I'm going to stop now since the end game is trivial other than optimization. Use some combination of KC-Ironworks to gain more Ironworks. Highway (KC not needed here) and maybe IW gaining Colony to draw the remaining Ironworks. Use KC-Ironworks to gain all the $1 Colonies and more. Everything else costs $0 so you can buy 13 more copies of anything with all those buys. Optimization probably involves Ironworks for Squire to get more +Buy.