Here's my optimized upsmash/shield stock-taking ledgetrap I've been theorycrafting/testing:

1) Whiff grab desync into (upsmash) [shield] by ledge. Spaced so upsmash's back hit hits neutral get-up and popo is close enough to dropshield fsmash the opponent's get-up attack animation.

2) React to any movement off ledge by letting go of all your buttons you're holding. I'd say the goal is to react within 18-20 frames as Nana's upsmash has 7 frames from charge to the hitbox + 6 frames of input delay + 3 frames before the back hitbox comes out, or 14 frames of lag from release, meaning you need to react fairly quickly. However, I think this is much easier in this context because the timing is fairly set, the only thing is that characters with faster neutral get-up animations like Samus or Pac-Man will require slight adjustments.

3) Immediately fsmash with popo to hit roll.

4) Shortly after, you can fsmash in the other direction to punish get-up attack. This can/probably should be a reaction but shouldn't be hard IMO because you don't need to think about roll anymore, just get-up attack.

Here's why it works:

Neutral get-up: loses to upsmash, the back hit of which has 3 active frames. The timing is consistent because you're just reacting to movement and most NGU animations are vulnerable on the same frame.  It's easy to react because you don't need to confirm that the neutral get-up animation specifically is happening, you just throw it out.

Roll: loses to dropshield fsmash. Roll is pretty slow and I tested vs. Lucario (a character with a very good roll) and could hit him (albeit barely) with dropshield fsmash on reaction to "any movement". Again, the timing is set so you don't need to confirm roll is happening, which makes it much easier. Also, because of the shielddrop making it slow (18-20 frames to react + 11 frame shield drop + 11 frame fsmash + 6 frame input delay = 48

Downsides to roll: you're hitting them in the wrong direction and a few characters might have really good roll animations and not be hittable. However, popo fsmash is pretty strong and can still kill from the wrong side pretty well, or at least lead to another edgeguard/ledgetrap situation on the other side of the stage.

Get-up attack: if the get-up attack is really fast (e.g. Lucario's) or you're just slow to react it hits your shield and you can drop-shield fsmash most characters on reaction. Even if you input the fsmash in the wrong direction to roll it won't come out because you can't buffer an option during the time your shield is hit (before shieldstun, so shieldlag I guess), so the fsmash to cover roll works as an option select.

If you parry get-up attack: if you did the f-smash to cover roll already then unfortunately you cannot just input another fsmash to the right to override it, it will read the first f-smash. HOWEVER, you have two solid options off the parry:

1) B-reverse blizzard. Specials are higher up on the buffer priority than smashes so this will override the fsmash, freeze them, and potentially lead to a follow-up. (Downside is that has to recover from the get-up attack before she can help.)

2) The IMO funnier and probably better option... put shield back up, immediately drop shield, and fsmash. The reason why this works is that shield is ALSO higher up on the buffer priority, so it will override the fsmash to the left, parry's 3 frames of extra advantage will cancel out the mandatory 3 frames of putting up shield, and then it's as if you just did drop shield -> fsmash again.

Of course, for all get-up attacks there are some characters who you cannot dropshield fsmash vs*, for these I would do dropshield dsmash or upsmash.

*Samus/Dark Samus, Dr. Mario, Ganondorf, Meta Knight, Pit/Dark Pit, Snake, Squirtle**

**even drop-shield dsmash is too slow for Squirtle and his GUA comes out so late you'll probably miss the parry, so in this case you probably want to exploit his GUA's slowness by reacting to it when dropping shield by putting the shield back up (it will override an fsmash to cover roll if you already inputted it) or just use a different ledgetrap

If you're too fast to drop shield for get-up attack: some characters have slower get-up attacks that might be a consistently timed shielddrop (e.g. a shielddrop on frame 19 with a 5 frame parry window would lose to a get-up attack that comes out on frame 24) but in truth I think this is unlikely because of the differences in animations: if you are just reacting to movement then IMO you will likely be slightly faster to react to roll because it moves position more quickly than other options, and that is a dead giveaway that they did an option, which in turn lets you dropshield fsmash for roll faster (which is important for hitting the end of their vulnerability). But get-up attack should take a few frames longer to react to because it's slightly more ambiguous that they picked an option (same with neutral get-up), so at least with how I react my reactions naturally tend to accomodate this without me "reading" the option. (The goal of this ledgetrap is to minimize reads.)


Ledgedrop -> aggressive options: These usually either whiff, fail to hit nana because of upsmash's slight low profiling and then get hit by nana upsmash, trade with nana upsmash, or hit nana but are unsafe and thus susceptible to a reaction with popo (due to shieldlag/shieldstun). I think p. much every time the Samus CPU tried ledgedrop dj fair they just got punished by my general reaction (didn't read what they were doing, just reacted to any movement), also tested vs. a Lucario CPU and they also just got punished most of the time. There are probably some characters that can bypass this but for this you just need to ledgetrump them next time. Speaking of...

Ledgestall: two options I like if you think they're going to ledgestall. One is to start the setup and then just immediately ledgetrump upsmash. Two is to start the setup, shield, jump oos, airdodge to ledge, and drag Nana with popoforce, also resulting in ledgetrump upsmash. You can also just wait it out and try to hit their invincibility as it goes away or feint doing by letting go of shield and then putting it back up (if they've figured out the ledgetrap a bit) but generally if you punish ledgestalling once or twice they should ideally be pressured into picking an option before the upsmash runs out.

Jump: This one's the mix-up option as usual but there are some decent ways to cover it. Of course if they jump into your upsmash then cool, free hit/kill. If they ledgejump but then hold back out of fear then you should jump oos with Popo on reaction to threaten the ledgespace. Again, you can cancel the fsmash to cover roll with a shield input which gives you more time to react. The way I do it is to generally just think "are they near me" and if not then I know they jumped and so I cancel the fsmash and then upair. If you are slow to punish the jump or they try to jump over you you can also up-B oos, which will cancel Nana's smash attack, and this is such a weird option that they are probably not watching out for that it can work.

You can also try to call it out by just giving up the main ledgetrap and bairing oos, but then you will probably lose to them picking roll and possibly get-up attack. to minimize this, after you bair oos (which requires you to cancel nana's smash attack), hold in and then use synced squall to cancel some of the end-lag of nana's attack, then hold out to cover roll and try and hit them back towards ledge, or punish a get-up attack that whiffed. If they did not whiff a get-up attack or do something dumb after a neutral get-up, then space the squall so it ends into position for a blizzwall ledgetrap instead (using squall desync), or if they timed a jump over you after your bair, then hold in to get center stage and corner pressure instead.

Note that you can also use the squall trick with squall oos after an upsmash that whiffed vs. neutral get-up to also continue pressure while protecting Nana.

Pros:

- can take stocks on all grounded options (jump is more of a read)
- however when optimized, doesn't give up jump for free/can still lead to a stock
- consistent to react to
- doesn't require complicated desyncs or desync kills that can easily be dropped
- fairly safe and non-committal
- very ambiguous as to what options are being covered/what the counterplay is
- can easily be mixed up into a ledgetrump instead

Cons:

- requires decent reactions/some practice
- takes time to set up
- loses to shieldbreakers/tomahawks
- kills roll much later than other options (unless they DI badly, which is certainly possible)
- some characters with unique get-up option frame data or with very long rolls might get past it




"Summary" of BBaller's (upsmash) [shield] option-select based ledgetrap (OSBL)

1) Use desync to set up (upsmash) [shield]
2) Let go of all buttons on reaction to movement

- (upsmash) > neutral get-up (3 active frames on the back hit, set timing for most characters, don't need to determine if it's a neutral get-up or not, just do it)
- (upsmash) > some aggressive ledgedrop aerials
- Popo shield punish or parry punish > some aggressive ledgedrop aerials
- Between the two, it is very risky for them to use an aggressive option unless they have a tomahawk/shield-breaking option, which can still be beaten sometimes

3) After releasing all buttons, can fsmash right after the shield drop to cover roll. This does NOT have to be a reaction to the ledgeroll animation itself but *can* be if you are practiced, just wait until the end of shielddrop to do it.

From here if you buffered the fsmash to beat roll you only need to worry about get-up attack and jump next, and get-up attack is easy:

IF get-up attack'd:

- and you shield it - shieldlag prevents fsmash to cover roll from coming out (option select), can easily react and turnaround fsmash the get-up attack

- and you parry it - fsmash directly if you didn't buffer an fsmash to hit roll (can even charge it slightly), otherwise tap shield and turnaround fsmash to override the fsmash you buffered to cover roll. The parry frames will let you react to this and the parry advantage makes it possible.

If their get-up attack is slow then you might get hit for reacting with shielddrop too fast, but this is unlikely IMO and can be adjusted for on a match-up-by-match-up basis.

IF they jump:

- (usmash)/[shield] > quick aggressive option (might even parry)
- aerial oos pressures/corners "jump into hold back" (i.e. if the opponent ledgejumps but then holds away from the stage as they're scared to jump over you) and from here you anti-air them or punish regrab
- up-air or even up-B oos (which will cancel nana's upsmash) > jumping over you

ADVANCED: you can cancel the buffered dropshield -> fsmash that you did to cover roll by tapping shield (buffer priority, see full explanation) and then jumping. This is advanced but doable and makes it so you don't *have to* give up ledgejump/pressure it late because you committed to punishing roll

CAN ALSO: pretend to set up the ledgetrap and then bair oos to pre-emptively cover jump, then squall back to cancel Nana's upsmash endlag/cover roll (this also can protect Nana from a get-up attack), then either pressure the air if they timed a jump **after** your bair, set up a blizzwall out of squall desync to corner pressure/ledgetrap if they did something else, or take center stage at worst. (Should have plenty of time to react to what happened.)

IF they start to ledgestall: can pretend to set up the usual ledgetrap and then instant ledgetrump out of dash or tap shield as a bait and then airdodge to ledge oos.

Cons: needs practice/IMO necessitates understanding option selects and frame data, takes time to set-up in-game
Pros: strong, reactionary, adaptable kill setup that can cover all options (but mainly the grounded ones)