There are two plausible moves, and maybe more:

(1) capture the 4-sided Xswing with value 1 and don't reroll the 20 sided die. This way

the 20-sided die is safe for at least one more turn and it can be rerolled later, when the opponent will have fewer dice.

(2) use the 20-sided die and capture the 10-sided die with value 4; you're rerolling it when the opponent's

dice can only sum to 5,10,15 and 6,11,16. It might not be so good in the future, and you capture a bigger die this turn.

(3) any other bright ideas?

Button Men Game #678131
Tournament Legal challenge, copying communication from game 678019

Skills in this game: Focus, X Swing

Player: ElihuRoot *Dead Dude* *Fanatic*
Your Button Man: Phoenix (4 6 f8 10 f20) Score: 24 (2 sides) Rounds Won/Lost/Tied: 2 / 0 / 0 (Out of 3 wins)
Your Captured Dice: None

4-sided die	6-sided die	Focus 8-sided die	10-sided die	Focus 20-sided die
1	6	4	2	6
6-sided die	10-sided die	10-sided die	12-sided die	X Swing (with 4 sides)
5	5	4	5	1

Opponent: alaric *Sci-Fied* *Silver Medal in Men's Boxing* *Silver Medal in Men's Marathon* *Silver Medal in Men's Synchronized Swimming* *Gold Medal in Men's Wrestling*
Button Man: Niles (6 10 10 12 X) Score: 21 (-2 sides) Rounds Won/Lost/Tied: 0 / 2 / 0
Captured Dice: None