This is my first “article,” so here goes... I love this combo, and I am sure other skilled players have used it, but I haven’t seen it mentioned much here: Watchtower/University...
A skilled player laughs when his opponent, who just reshuffled, buys a $5 card over a much-needed Duchy at the end of the game. Why? Because he is never going to see that card again. Decks brimming with expensive Actions and Golds don’t win games; Green wins games. Dominion is all about tempo--most of the time, you want $5 actions and Golds, and then you want Provinces and Duchies, and then the game ends.
This is why it’s generally faster to buy the cards you want rather than to buy other cards that will eventually gain cards that aren’t even that great. Concordantly, Workshop is terrible, and Ironworks is mediocre. University is better in the sense that it can gain useful $5 cards, but its awkward cost means it’s essentially more expensive than the cards you want to gain with it. At some point, the University player’s superior rate of card-gaining will kick in, but it won’t be in the critical early stages of the game. Unless the $5 card benefits from University’s extra actions--like Torturer--you really are better off reaching for those $5s with a Silver/Silver-equivalent opening rather than a Silver/Estate-equivalent opening.
Watchtower, however, massively tips the scales in favor of pursuing Universities. Watchtower’s reaction ability can place the cards you gain with University on top of your deck. Since University is a village that doesn’t increase your hand-size, you can then play Watchtower to draw the card you just gained (and a few others, too), and play it. Being able to immediately play gained cards--Wharfs, Markets, Highways, Laboratories, Witches, Governors, Torturers, etc.--is a huge advantage. Additionally, the extra draw from University--and presumably from some of the cards you are gaining--will cycle your deck faster, allowing more playing of Universities, and more gaining of useful cards. Your opponent may get a few $5 cards (and Golds) faster than you, but with Watchtower and University, you will catch up very, very quickly.
Watchtower/Potion is the opening here. The best case scenario is drawing them together with CCE, buying University, and putting it on top of your deck for dramatically accelerated gaining. But if that doesn’t happen, Watchtower’s draw ability at least improves your odds of picking up a University before the first reshuffle. As the game proceeds, you should buy a University whenever you have a Potion, racking up probably 3 or 4 of them. You will also want a comparable number of Watchtowers.
That’s really all there is to it. Other Potion-cost cards make the combo more appealing, of course, by giving you something else to buy if you tire of Universities. Since you’ll be overloaded on Actions and moving through your deck rapidly, the option of grabbing Possessions or Golems or Vineyards is a huge plus.
Finally, if there aren’t many good $5 or $4 Action cards, this is obviously a combo to avoid. But the presence of Watchtower makes University much less avoidable than it usually is, because you will actually get to play that last $5 Action card before the game ends!
http://councilroom.com/game?game_id=game-20120402-211639-3af45fa6.htmlHere is a game where Watchtower/University gets me 5 Colonies and 8 Great Halls in just 15 turns. Neither of us played perfectly, but it's clear that Watchtower/University allows for a killer engine here. On Turn 8, I gain an Upgrade, a Great Hall, and 4 Highways.
http://councilroom.com/game?game_id=game-20120516-112615-69a32b25.htmlAnd here is a more recent game where Watchtower/University allows me to overcome my opponent, who got a scarily strong 5/2 start with Governor/Duchess. (Opening 4/3 against a 5/2 Governor opponent is often GG.) Notice that I still lose the Governor race 4 to 6, but the fact that I can use my Governors quicker than he can gives me an edge. Also, notice what I do on the final turn. I need the last Province, but only have $5 in hand, plus University and Watchtower...
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Edit 1: Added Vineyards to the list of other Potion cards with which this works.
Edit 2: Added sample games.