Dutching

[madmick50]

Anyone know where I can find simple to understand comprehensive guide on how to do dutching. I'm particularly interested in the under over 2.5 market for soccer.

[munk]

Don't know if you'll like this if you're not maths type person, but here goes:

When dutching the basic principle is that the sum of the reciprocals of each of the decimal odds must be below 1 for the match to be an arb. (A reciprocal is just 1 divided by the decimal odds - so if 2.1 is the decimal odds, 1/2.1 is the reciprocal.)

So, say in the simplest case you have this over/under 2.5 goals event (importantly where only one can be the winner):

Over Odds: 2.1
Under Odds: 1.9

Then the sum of the reciprocals is:

1/2.1 + 1/1.9 = 1.0025062656641604010025062656642(!)

so that's just about evens, you'd not win or lose anything.

The same principle applies to however many selections are in your match - so if it's a 1x2 event like football, you'd just add up the reciprocals of the Team1, Team2 and Draw decimal odds:

1/T1 + 1/T2 + 1/D

and if that's below 1 then again it's an arb.

The easiest way I've found to do this calculation is just using Windows 'calc' program. Open up calc ('windows-key + r', type in 'calc', hit enter). Enter in the first decimal odds and hit 'r' (this gives you the reciprocal of the first selection's odds), hit '+', enter in the next decimal odds, hit 'r' again, etc until you've added each of your reciprocals. Again if it's under 1 you've got an arb.

You can also use calc to work out what the minimum odds are you need given one selection.

Say in the above you know the first odds are 2.1. enter 2.1 in calc, hit 'r', then press '-', then press 'enter' twice and then add 1. Finally press 'r' again and it'll tell you the minimum decimal odds you need for the second selection for it to be an arb. In this 2.1 case the result you get is 1.9090 so anything over for the second selection would be an arb.

Actually there's an easier way you can change the sign of a number by pressing 'F9' which I just found out.

So, enter 2.1, press r, press F9, add 1, press r. That gives you the minimum odds you need for an arb on a two selection event where the first odds are 2.1.

You can also do it by subtracting one from the first odds, calculating the reciprocal and then adding one (I think?!).

ie if first odds are 2.1:
1/(2.1-1) = 1/1.1 = 0.909090

add on 1: 1.909090 - anything over 1.909090 is an arb for that match.


I read somewhere else that a good way of spotting an arb is to add up the decimal odds of all the selections in your match and then if the square root of that sum is more than the number of selections in the match, there's a chance it could be an arb.

So for 2 selections, if the square root of the sum of the decimal odds is more than 2 then there's a chance there's a match. This is based on the principle that for a match with 2 selections in it, the 'optimal' odds for each selection are 2:

Odds1: 2
Odds2: 2

Using the calc from above, the sum of the reciprocals is: 1/2 + 1/2 = 1, so that's the trivial no win/lose match.

Using the 'rough check' method, 2+2 = 4, square root of 4 is 2, so it's not an arb but it's close (since 2 is not more than 2).

For 3 way dutches it's the same kind of thing - 3 is the optimal odds for each selection because 1/3 + 1/3 + 1/3 = 1.

Personally I've never had much luck with that square root business.

And in fact generally I've only ever had one dutch, so perhaps I'm not the best person to answer at all!!! I think the above is true though.

There's actually another cool way of spotting arbs using american odds but I'll leave that to someone else to explain or I'll do it later when I've got more time.

[madmick50]

Many thanks for such a thorough explanation (must have took you ages). I am a reasonably competent maths type person and what you say does make sense to me (after reading it a few times!). I'm sure it will make even more sense when I try doing some examples of my own. Once again many thanks for taking the time to answer my query.

[munk]

I forgot to say, once you've found a match using the above methods to quickly check if it's on or not, goto one of the dutching websites or download the multiback.xls spreadsheet from here and you can work out the stakes required etc:

http://www.money-for-old-rope.co.uk/multiback.xls

Good luck

[madmick50]

Thanks again.

[Jono258]

i might have to read that a few more times just not sinking in but its been a long day!

[munk]

Lazza also posted a good dutching post here:

http://thegamblersunderground.com/al...html#post16143

[Jono258]

will read that too!

[1mstgt]

hello there,I've been doing this a while now and keep seeing dutch in topbetter,could anyone tell me what this is and how to do it
Cheers,sam

[Andy]

It involves betting on all possible outcomes at different bookmakers rather than laying bets at betfair, sometime you can dutch with two sites and sometimes you need three, it depends on the market you are betting on.

Can you give an example of what you have seen at Topbetter and then I (or someone better than me) will be able to explain what you would do with that information?