SHORT ANSWER
Never. Each spin in Fist of Destruction is independent. A losing streak has no memory and does not make the next spin more likely to win or trigger a bonus. Increasing bets during a cold run raises your expected loss, not your expected wins.

Why chasing losses feels logical but isn't

The intuition behind raising bets during a losing streak — that a win must be coming soon — is called the gambler's fallacy. It treats a random sequence as if it has a balancing mechanism. Fist of Destruction's RNG has no such mechanism. Each spin is a fresh 34% or 66% event. The reel does not know it has produced 20 consecutive losses. The 21st spin is still 34% likely to produce any win, the same as the first spin.

What does change when you raise your bet: the absolute value of each subsequent spin, meaning losses become larger immediately and wins — when they come — are proportionally no more likely to cover the accumulated deficit.

The martingale on a slot — what the math says

A classic martingale doubles the bet after every loss to recover everything with one win. On a slot with a house edge, this fails for a specific mathematical reason: the winning spin does not necessarily return your full bet, it returns a fraction of it based on the win multiplier.

Fist of Destruction's base game win distribution clusters around 0.2x to 2x. If your doubled bet wins, a 0.5x return on a 2x bet still leaves you at a net loss for the sequence. You need a win above 1x — which happens in roughly 12 to 14% of spins in my tracking — just to break even on a single doubling step. The math gets worse as the streak extends.

SEQUENCEBETRUNNING TOTAL WAGEREDWIN NEEDED TO BREAK EVENPROBABILITY OF THAT WIN
Spin 11.001.00Above 1x~13%
After 3 losses8.0015.00Above 1.88x~8%
After 5 losses32.0063.00Above 1.97x~8%
After 7 losses128.00255.00Above 1.99x~8%

What actually varies with bet size

Two things legitimately change with a larger bet. First, if you do trigger the bonus — at any bet size — larger bets produce larger absolute returns from identical multipliers. A 100x bonus pays 100 at 1.00 per spin but only 10 at 0.10 per spin. Second, the buy feature cost scales with bet size, so if you want to buy the Uppercut bonus at 50x stake, a higher base bet makes that a more significant commitment.

Neither of these is a reason to raise bets during a losing streak. The first is true regardless of when you raise — you could raise at any point in a session for the same effect. The second is about deliberate buy feature strategy, not streak management.

The only valid reason to change bet size mid-session

If your bankroll has grown significantly from an early bonus win, stepping up your base bet is defensible — you are gambling with profit rather than risking your starting bankroll disproportionately. This is not chasing losses. It is repositioning from a position of strength.

Conversely, if your session is going badly, reducing your bet to extend spin count — giving yourself more opportunities to catch a bonus naturally — is the one bet-size adjustment that makes mathematical sense in a losing session.

The practical rule: Set your bet size before the session based on your bankroll ratio, not based on results during the session. Decide at the start: this is my stake, this is my stop-loss. Changing bet size in response to outcomes is the most reliable way to accelerate losses.

BOTTOM LINE
Do not increase bets during a losing streak in Fist of Destruction. The streak has no predictive value for future spins. Raising your bet raises your expected absolute loss per spin, period. If anything, reduce bet size during a bad run to extend your session and increase your spin count before the bankroll is gone. The bonus comes when the RNG decides — your bet size does not influence when that is.