Matchup Summary (Win Condition and Game Plan)
This matchup gets ugly when Mythra is allowed to run directly through Bowser Jr.’s pre-setup space and start the usual landing trap and ledge cycle with her speed and sword range. Bowser Jr. has the tools to scatter those routes with setup, but his close-range defensive answers are not especially fast, so the neutral structure has to stop Mythra from taking that first clean run-in.
Bowser Jr. does best by using Mechakoopa, cannonball, and pullback movement to shift Mythra’s dash start points, then layering fair, uair, or a delayed cart only after those lanes are bent. Mythra’s speed is the obvious problem, but her kills are still more setup-dependent than her pressure, so once she is forced into jump-overs or Photon Edge entries, her landing and ledge choices become much more manageable to read.
The frame table shows Jab 1-3, Forward Tilt, Up Tilt, Down Tilt, Dash Attack, every smash attack, and Side B are all punishable mainly through Up Smash (7f), OOS Uair (9f), or Grab/OOS Nair (10f). By contrast, Forward Air, Back Air, and Down Air usually stop at Up Smash as the realistic punish, Up Air has no immediate punish at all, and Neutral B only becomes truly open at the close end of its shield data, so forcing a big shield-drop swing is often worse than covering Mythra’s next landing or retreat spot with setup.
Stocks are most repeatable when Bowser Jr. uses uair to keep Mythra above him, then leaves Mechakoopa and cannonball active at ledge to cover jump with fair and neutral getup or roll with up smash. Her recovery path is fairly linear, so holding ledge pressure is usually better than overchasing offstage and exposing Bowser Jr.’s own post-Up-B weakness.
Full Move Frame Quick Reference
| Opponent Move | Startup | On Shield | Bowser Jr. OOS Candidate Moves | Barely Missed Moves |
|---|---|---|---|---|
| Jab 1 | 2 | -15 |
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| Jab 2 | 4 | -23 |
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| Jab 3 | 4 | -20 |
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| Rapid Jab | 8/12/16… | — | ||
| Rapid Jab Finisher | 6 | -27 |
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| Forward Tilt | 8 | -11 |
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| Up Tilt | 7 | -14 |
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| Down Tilt | 5 | -11/-10 |
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| Dash Attack | 9 | -22 |
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| Forward Smash | 14 | -26 |
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| Up Smash | 9/12/17/22/26 | -40/-21 |
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| Down Smash | 8/14 | -28/-30/-22/-24 |
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| Neutral Air | 8 | -10 |
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| Forward Air | 8 | -7 |
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| Back Air | 10 | -7 |
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| Up Air | 9 | -5 |
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| Down Air | 13 | -7 |
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| Neutral B | 9/20/30/40—69/80/90/99/109 | -21 — -8 |
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| Side B | 18/25/32/39/46/54 | -47 |
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| Up B | 10/40 | ** | ||
| Down B | — | — | ||
| Grab | 6 | — | ||
| Dash Grab | 11 | — | ||
| Pivot Grab | 12 | — |
Win Condition Checklist
- Use Mechakoopa, cannonball, and pullback movement to interrupt Mythra’s run-ins first, then cover the jump-over or Photon Edge landing with fair, uair, or cart.
- After blocking Jab 1-3, Forward Tilt, Up Tilt, Down Tilt, Dash Attack, any smash attack, or Side B, take the listed punish with Up Smash (7f), OOS Uair (9f), or Grab/OOS Nair (10f).
- After blocking Forward Air, Back Air, or Down Air, do not overforce a larger punish than Up Smash. Re-cover the landing and retreat instead with Mechakoopa or cannonball.
- Treat cart as the payoff after setup, not as a raw burst option into Mythra’s up smash, up B, or preemptive sword hitboxes.
- Build kills through juggle and ledge control, using uair to keep Mythra above you and then forcing the ledge tree into fair, up smash, and Mechakoopa coverage.
Actions to Avoid
- Chasing on the ground without setup and walking straight into Mythra’s Down Tilt, Dash Attack, and landing-trap pace.
- Shield-dropping for oversized punishes after Forward Air, Back Air, and Down Air, then getting whiff-punished and losing stage again.
- Throwing out raw cart and letting Mythra stop it with up smash, up B, or a pre-placed sword hitbox before your offense starts.
- Overcommitting offstage, exposing Bowser Jr.’s post-Up-B body, and giving away a ledge situation that was already winning.